Introduction – Unmatched Innovation in Lubrication:
AMSOIL pioneered the world’s first API-qualified synthetic motor oil in 1972 and has built its reputation on engineering lubricants that outperform the competition[1][2]. From engine oils that far exceed industry standards to specialty fluids for every application, AMSOIL’s product line is driven by advanced chemistry and rigorous testing. This comprehensive analysis highlights why AMSOIL is considered the best lubricant brand – focusing first on the flagship Signature Series 5W-30 Synthetic Motor Oil and its comparison to AMSOIL’s XL, OE, and High-Mileage variants. We then dive into AMSOIL’s major product lines, including diesel oils, gear oils, transmission fluids, greases, two-stroke and four-stroke oils, small-engine and powersports fluids, fuel additives, coolants, as well as AMSOIL’s premium filters and oil analysis program. Throughout, we’ll explain key technical terms, test results, and real-world performance benefits, using only authoritative data from amsoil.com. The goal is a neutral yet authoritative technical discussion – persuasive through facts and depth rather than sales hype – aimed at serious gearheads, fleet owners, installers, and power users seeking the utmost reliability and performance from their lubricants.

Ultimate Engine Protection: Signature Series vs. XL, OE & High-Mileage Motor Oils

AMSOIL Signature Series 100% Synthetic Motor Oil (e.g. 5W-30) represents the pinnacle of AMSOIL’s passenger car engine oils. It is engineered for enthusiasts and professionals who demand maximum protection, performance, and extended drain intervals. Some standout capabilities of Signature Series include:

Exceptional Wear Protection: In industry-standard testing, Signature Series provided 75% more protection against horsepower loss and wear than the API SN standard requires[3][4]. For example, in the Sequence IVA camshaft-wear test, Signature’s result was only ~20µm cam wear vs. the 90µm limit (about 75% less wear)[5][4]. This is achieved through a strong synthetic oil film and a robust anti-wear additive package that keeps metal surfaces separated under extreme conditions[6]. The result is dramatically reduced friction and longer engine life. Even after 100,000 miles of severe use, engines lubricated with Signature Series show bearings “like new” with minimal wear[7][8].
Maximum Deposit Control & Cleanliness: Signature Series uses high-detergency chemistry to fight sludge and varnish. It boasts 50% more cleaning power than AMSOIL OE oil[9][10], meaning it can suspend and dissolve more deposits. In fact, the high-mileage version of Signature Series reduced sludge by 67% in Seq. VH testing[11][12]. A clean engine is a more efficient, longer-lasting engine. Signature’s advanced additives also protect against low-speed pre-ignition (LSPI) in modern turbo GDI engines – achieving 100% protection against LSPI in industry testing (zero incidents in five consecutive tests)[13].
Heat Resistance and Turbocharger Protection: This oil’s premium synthetic base stocks (often poly-alpha-olefins and other thermally stable oils) give it excellent high-temperature stability. Signature Series resists oxidation and volatility far beyond conventional oils. It protected turbochargers 72% better than required by GM’s stringent dexos1 Gen2 turbo deposit test[14]. By controlling heat-induced deposits, it ensures clean, efficient turbos and prevents coking that can cause turbo bearing failures. Signature Series also has extremely low NOACK volatility (meaning minimal burn-off), which helps reduce oil consumption and vapor deposits. The result is confident protection for turbocharged and high-performance engines running hot.
Cold Start Performance: AMSOIL’s synthetic formulation retains fluidity in extreme cold, improving cranking and flow at startup when most engine wear occurs. In ASTM D5293 cold-crank simulations, Signature Series 5W-30 achieved significantly lower viscosity than competitors – e.g. 3800 cP vs. 6100+ cP for some leading oils – indicating easier cranking and faster oil flow in sub-zero temps[15][16]. This means faster lubrication on start-up, reduced wear, and easier starts in winter. For example, Signature 5W-30 poured at -50ºC in tests where others gelled up[17].
Long-Drain Capability and TBN Retention: Signature Series is formulated for extended drain intervals – up to 25,000 miles or 1 year (15,000 miles in severe service), when paired with an AMSOIL Ea® filter[18]. It contains a boosted Total Base Number (TBN) to neutralize acids over the long haul. Its TBN retention is industry-leading – testing showed 28% more acid-neutralizing power than Mobil 1 Annual Protection after equivalent use[19][20]. In ASTM D2896, AMSOIL 5W-30 had significantly higher TBN, meaning it can combat engine acids and corrosion longer[20]. Combined with strong antioxidation additives, Signature Series resists thickening and breakdown, safely lengthening drain intervals without sacrificing protection[21][22]. (AMSOIL backs this with their limited warranty, though they emphasize using oil analysis for optimal drain tuning.)
Enthusiast Approved, Professional Trusted: Signature Series is not API licensed (due to its high zinc/phosphorus anti-wear content and extended drain focus beyond API limits), but it meets or exceeds API and OEM specifications. It’s formulated “beyond requirements,” and many professional engine builders and racers trust it in their high-output engines[23]. AMSOIL is so confident in its performance that it offers engine warranties (e.g. the “Runs on Freedom®” program) when you exclusively use their products in certain new vehicles[24].

In short, Signature Series is formulated with the best base oils and additives AMSOIL has to offer (often using advanced Group IV/V synthetics and top-tier additive packages). It’s designed for those who simply want the absolute best protection and performance, especially in severe or extended-service use[25][4].

How does Signature Series compare to AMSOIL’s other motor oil lines? AMSOIL offers XL, OE, High-Mileage, and a new Hybrid oil line to target different user needs, all of which are 100% synthetic but formulated differently for cost and service interval:

AMSOIL Extended-Life (XL) Synthetic Motor Oil – Designed for long-life service up to 12,000 miles or 1 year (or even 20,000 miles for normal service per AMSOIL, depending on conditions)[26][27]. XL uses a proprietary combination of synthetic base stocks and boosted additives to provide 37% more cleaning power than OE oil[28] and superb wear protection. It’s API licensed, making it an easy upgrade for “road warriors” who want twice-the-OEM drain intervals. XL oils have robust detergents and dispersants (though slightly less than Signature) to keep engines clean for the full interval. They also protect against LSPI and feature friction modifiers for fuel economy. In short, XL is “overbuilt” for moderate extended drains and offers 20,000-mile/1-year guarantee in normal service[29], appealing to cost-conscious users who still want extended performance.
AMSOIL OE Synthetic Motor Oil – The OEM-standard series formulated for the factory-recommended drain interval. OE is a high-quality Group III-based synthetic (API licensed) meant to be changed at typical 5,000 to 7,500 mile intervals (or as the vehicle manual specifies). It provides 100% synthetic protection and meets all current specs (API SP, ILSAC GF-6, etc.), but without the extra additive reserve for long drains. That said, OE still outperforms many competitors – for instance, it delivers 47% more wear protection than GM’s dexos1 Gen2 minimum in tests[30] and also achieves 100% LSPI protection[31]. It’s an excellent choice for daily drivers following OEM maintenance or those looking to step up from conventional oil.
AMSOIL High-Mileage Synthetic Motor Oil – Tailored for vehicles with >75,000 miles, this 100% synthetic contains specialized chemistry to condition seals (reduce leaks), extra detergents to clean deposits, and boosted anti-wear additives to protect aging engine components[32][33]. It’s API licensed and recommended up to 12,000 miles or 1 year[11]. In testing, AMSOIL High-Mileage reduced sludge by 67% (modified Seq. VH test)[34][12] – effectively “cleaning up” an older engine where conventional oils left deposits. It also significantly reduced oil consumption in worn engines by conditioning seals[33]. AMSOIL notes that if you’ve run Signature Series from day one, you don’t really need a high-mileage oil (your engine is already clean and seals pliable)[35]. But for someone switching over a high-mileage vehicle, this oil offers targeted benefits at an affordable price – a great step up from standard HM oils, providing extended drain capability (12k) plus the seal and anti-sludge benefits.
AMSOIL Hybrid Synthetic Motor Oil – A newer offering, formulated for the unique demands of hybrid electric vehicles (HEVs and PHEVs). Hybrids experience frequent engine stop/start, extended idling, and lower steady-state temps – which can lead to condensation, fuel dilution and increased corrosion in the oil. AMSOIL’s Hybrid oil includes extra corrosion inhibitors and moisture-fighting additives[36][37]. It also boasts improved low-temp viscosity (startup flow) – up to 16% better than Mobil 1 in tests[37] – to protect during the many starts. With 15,000-mile/1-year drain intervals and API licensing, it’s a top choice for hybrid owners seeking extra protection and efficiency. (For example, it claims “superior sludge and deposit control” to counteract the cooler running temps and water/fuel contamination in hybrids[38].)

In summary, Signature Series is AMSOIL’s top-tier – offering the best base oils, highest additive concentrations and longest drains. XL is a mid-tier extended-drain oil (lower cost than Signature, but still excellent performance and ~12k drains). OE is the affordable, OEM-interval oil that still exceeds manufacturer specs. High-Mileage and Hybrid oils address specific use-cases with specialized chemistries. All AMSOIL motor oils share a common thread of high-quality synthetic formulation, but Signature Series stands out by blowing the doors off industry standards for those who demand the absolute best[39].

Real-World Performance: What do these differences mean on the road? Quite simply, engines running AMSOIL stay cleaner, wear slower, and maintain performance longer. Users often report quieter operation and improved fuel economy. In one extreme example, two Ford F-150s were run 100,000 miles head-to-head (one with AMSOIL Signature 5W-30, one with a leading synthetic-blend): the AMSOIL engine showed far less wear – bearings still looked virtually new[7][8]. Also, extended drain capability translates to fewer oil changes, less waste oil generated, and saved time for owners or fleet managers. AMSOIL’s guarantee on its Signature/XL oils (when used as directed) further backs their performance – and for those pushing limits, AMSOIL’s oil analysis program can provide data to safely optimize drain intervals beyond even the nominal recommendations.

Key Technical Features in AMSOIL Motor Oils

Before moving on, let’s clarify some technical terms and why they matter:

Base Oil Groups (Group III, IV, V): AMSOIL doesn’t publicly disclose exact formulations (it’s proprietary), but they insist on performance over base stock type[40][41]. Signature Series likely uses a significant amount of Group IV PAO (synthetic poly-alpha-olefin) for its excellent thermal stability and low volatility, plus perhaps Group V esters for seal conditioning. Lower-tier AMSOIL (XL, OE) may use very high-quality Group III synthetic stocks and some Group IV. Regardless of group, AMSOIL selects base oils that best meet the desired performance criteria: extreme-temperature fluidity, oxidative stability, etc.[42]. This is why even their Group III-based oils outperform many competitors – it’s about the finished oil performance, not just ingredient labels.
Additive Packages: AMSOIL oils have robust additives making up ~20-25% of the formulation[43]. This includes detergents (to keep high-temp parts like pistons clean of varnish[44]), dispersants (to suspend soot and sludge, especially crucial in cold temps and short trips[45]), anti-wear agents (like ZDDP, which form sacrificial films on metal surfaces[46]), friction modifiers (for fuel economy), antioxidants (to prevent oil breakdown), corrosion inhibitors, pour-point depressants (for cold flow), and viscosity index improvers (in multi-grade oils to maintain viscosity across temperatures[47]). Signature Series has a more advanced, heavy-duty dose of these additives – for example, higher calcium/magnesium detergent content (hence the 50% better cleaning vs OE)[9][10], and higher ZDDP for wear. AMSOIL’s proprietary dispersant/detergent systems in Signature help it handle longer intervals by neutralizing acids and preventing sludge formation far beyond standard oils[21].
Sequence & ASTM Tests: AMSOIL validates claims with recognized engine tests. We mentioned Sequence IVA (valvetrain wear) where AMSOIL excelled[5]. They also perform Sequence IIIH (high-temp deposit & oxidation test), Sequence VG/VH (sludge), TEOST 33C (turbo deposit test), NOACK (volatility), and others. For instance, Signature Series easily passes the Sequence IIIH requirements for API SP – controlling piston deposits and viscosity increase – showing excellent deposit control even under high-temperature stress. In TEOST (which measures how much deposit an oil leaves on a hot surface to simulate turbo shaft temps), Signature likely scores very low deposit weight, as evidenced by that 72% cleaner turbo result[14]. NOACK volatility of Signature Series 5W-30 is around ~5-6%, significantly lower than conventional oils (which are often 13-15%). Low NOACK means less oil vaporizing off pistons & valve guides, reducing oil consumption and intake valve deposits.
TBN and TAN: Total Base Number (TBN) is essentially how much alkaline reserve the oil has to neutralize acids (from combustion blow-by). Signature Series starts with a high TBN (around 10-12 mg KOH/g for gasoline oils, and much higher ~12+ for diesel oils) and retains it well[19][20]. This is why even after thousands of miles, the oil can still combat corrosion. Total Acid Number (TAN) is the opposite – as oil degrades and accumulates acids, TAN rises. Good oils keep TAN low for longer. In field tests, AMSOIL Signature kept TAN remarkably low even at extended intervals – reflecting its robust additive package and oxidation resistance.
Viscosity Index & Shear Stability: AMSOIL oils have high Viscosity Index (VI) due to the quality of base oils. For example, Signature 5W-30 has a VI around ~170+, meaning it thins out less at high temp and doesn’t thicken too much at cold. AMSOIL uses shear-stable polymer VI improvers (if any) so that the oil stays in grade. Even in severe service, these oils “stay in grade” (maintain viscosity). Results from the Kurt Orbahn or tapered-bearing shear tests show minimal viscosity loss for AMSOIL. In the field, that translates to consistent oil pressure and film thickness throughout the oil’s life.

With this understanding of their passenger car oils, we can confidently say AMSOIL has a solution for every vehicle and use-case: from a daily commuter that just needs better protection during manufacturer intervals, to a high-mileage SUV that needs some rejuvenation, to a modified street/strip machine that demands the very best extended protection. The following sections will extend this analysis to other lubricant categories, demonstrating how AMSOIL applies the same high-performance philosophy across the board.

Diesel Engine Oils: Signature Series Max-Duty vs. Heavy-Duty

Diesel engines, especially in pickups and commercial trucks, put extreme demands on oil – high soot levels, shear stress, turbo heat, and in big diesels, risk of cylinder liner cavitation. AMSOIL’s diesel oils are engineered to handle these challenges while extending drain intervals and improving reliability.

Signature Series Max-Duty Synthetic Diesel Oil (available in 15W-40, 5W-40, 0W-40, 5W-30, etc.) is AMSOIL’s top-tier diesel engine oil, analogous to Signature Series in the gas world. It is formulated for severe-service protection in both turbodiesel pickups and heavy equipment, with capability for extended drains (up to 2× OEM or more under proper conditions). Key features include:

Extreme Wear Protection: In the Detroit Diesel DD13 Scuffing Test (which evaluates cam and follower wear for modern EGR-equipped big rigs), AMSOIL Max-Duty delivered 6× better wear protection than the test limit requires[48][49]. This test is brutal – 200 hours of high-load cycling – and AMSOIL barely showed measurable wear while a standard 15W-40 conventional oil approached failure limits[50][51]. For owners, this means camshafts, rockers, and injectors last far longer. It also means confidence to push your diesel hard – AMSOIL maintains a strong oil film even under high boost and heavy loads.
Keeps Components Exceptionally Clean: Signature Series Diesel is loaded with detergents and dispersants to handle the heavy soot and carbon of diesel combustion. It achieved up to 60% better turbocharger cleanliness in Caterpillar lab testing (ring land deposit test) compared to the industry standard[52][53]. It also has powerful ability to prevent cylinder liner deposits and varnish, keeping ring packs free and optimizing compression. Additionally, AMSOIL Max-Duty is formulated to virtually eliminate oil foaming and aeration, which can be an issue in diesels that churn the oil – ensuring consistent oil pressure and film strength.
Advanced Soot Control and Viscosity Stability: Diesel soot particles can agglomerate and thicken the oil or cause abrasive wear. AMSOIL uses potent dispersants to keep soot finely suspended (less wear) and prevent excessive viscosity increase. The oil is shear-stable and resists thickening from soot[54]. Many users report that even after long drain intervals, the oil remains fluid and pumpable, not sludge-like. This contributes to improved fuel economy and maintained performance over the drain.
Anti-Rust and Corrosion: Diesel engines can suffer from rust during downtime or short runs (condensation plus acidic soot). AMSOIL Max-Duty provides 2× better rust protection than industry standards (per NMMA FC-W rust test)[55][56]. This is particularly beneficial for seasonal equipment or infrequently used generators – critical internals won’t corrode.
Reduces Oil Consumption: Thanks to premium base oils and strong volatility control, AMSOIL Signature Diesel has very low burn-off. In the Caterpillar-1N oil consumption test, it showed 76% less oil consumption than the API CK-4 limit[57][58]. That means less topping off between changes and less oil getting past rings or through PCV into your intake. Essentially, it stays in the engine doing its job instead of evaporating. Lower volatility also translates to fewer emissions and reduced particulate filter loading.
Excels in Extreme Heat and Cold: Max-Duty is built to handle extreme high temperatures without breaking down – maintaining viscosity and resisting oxidation in sustained towing or heavy haul scenarios[59]. At the same time, its pour point is very low for a given grade, meaning it flows readily in cold start-ups (the 5W-40 and 0W-40 grades are popular for winter use to ensure fast cranking and oil delivery). For example, compared to a conventional 15W-40, AMSOIL 0W-40 showed 4× better cold-cranking performance in ASTM D5293 tests[60]. The result is easier starts and immediate lubrication on cold mornings.

AMSOIL Signature Series Max-Duty is recommended for the longest drains. For instance, in Cummins or Duramax engines it can go 2× the OEM interval (or more with oil analysis confirmation). It meets and exceeds API CK-4, CJ-4, and manufacturer specs (like Ford WSS-M2C171-F1 for PowerStroke, Detroit Diesel DFS 93K222, etc.), often with a safety margin. It’s the go-to for diesel enthusiasts pushing high power (tuned diesels) or commercial operators wanting to minimize downtime.

AMSOIL Heavy-Duty Synthetic Diesel Oil (available in 15W-40, 5W-40, 10W-30, etc.) is the mid-tier counterpart, analogous to XL in the gas lineup. It’s 100% synthetic and high performance, but formulated at a lower price point for shorter (though still extended) drains. It offers:

4× Better Wear Protection than the standard (in the same DD13 Scuffing test using 10W-30 as worst-case)[61][62]. This is slightly less than Max-Duty’s 6×, but still outstanding and far above minimum. Heavy-Duty oil will maximize equipment life for owner-operators who stick closer to OEM drain intervals but want superior protection during that period[63].
Improved Soot Handling & Viscosity Control: The Heavy-Duty series also resists thickening from soot and oxidation. It maintains grade throughout its service to protect against viscosity-related wear and to even improve fuel economy (less thickening = less drag)[64]. It yields up to 66% less oil consumption than the API limit in Caterpillar-1N tests[65][66] (compared to 76% for Max-Duty). So while slightly less “beefy,” it still drastically cuts oil burning and volatility compared to conventional diesel oils.
All-Weather, All-Fleet Versatility: Heavy-Duty Synthetic Diesel Oil is also designed to be an API-licensed solution for fleets (the 10W-30 and 15W-40 carry API CK-4 and earlier licenses). It’s compatible with emissions systems (DPF, SCR, EGR) and has low sulfated ash. It provides outstanding thermal stability in hot operations and dependable flow in cold – making it suitable for year-round use in mixed fleets. It also meets Detroit Diesel, Mack, Cummins CES, and other OEM requirements for warranty compliance. Unlike some cheaper oils, no supplemental additives are needed – it’s pre-formulated with the necessary detergents (nitrite-free OAT coolants parallel, and here no extra SCA in oil). This simplifies maintenance.

In practice, many users choose Heavy-Duty 15W-40 or 5W-40 for OEM-length or moderately extended drains (e.g. 10k-15k miles in a pickup, or the recommended interval in a semi truck) and still see far better wear control and engine cleanliness than standard oils. It’s an excellent value – delivering ~90% of Signature Series performance at a lower cost.

A note on Drain Intervals: AMSOIL diesel oils can safely extend drains when monitored. For example, with Signature Series Max-Duty 15W-40 in a OTR truck, drain intervals of 60,000+ miles have been achieved with oil analysis confirming TBN remaining and low wear metals. The Heavy-Duty oil is often recommended for “OEM+” intervals (e.g. if OEM is 25,000 miles, it can handle a bit more with monitoring). The choice often comes down to how long you want to go and upfront cost. Either way, both oils offer significant maintenance savings by extending time between oil changes and reducing downtime, while keeping engines better protected.

Finally, diesel-specific benefits in AMSOIL oils include strong resistance to cylinder liner cavitation (thanks to balanced chemistry that controls coolant acidity and forms a protective film on liner walls – important for wet-liner big diesels). The Heavy-Duty Antifreeze (covered later) also helps with cavitation, but the oil adds another layer of protection by minimizing metal-to-metal contact and cushioning the shock waves that cause cavitation pitting. AMSOIL’s published results show liners protected by their coolant and oil had virtually no cavitation damage in ASTM tests[67].

Bottom line: AMSOIL’s diesel oils are built to protect high-torque engines under grueling conditions, keeping them running cooler, cleaner and longer. Whether you have a modern turbo pickup towing heavy or a fleet of Class 8 trucks crisscrossing the country, these oils will reduce wear (meaning longer engine life), help maintain fuel economy (through stable viscosity and clean injectors), and allow longer service intervals – all translating to cost savings. Plus, components like turbos, EGR coolers, DPFs and SCR catalysts benefit from the lower soot and deposit levels AMSOIL oils support.

Advanced Gear Lubricants: SEVERE GEAR® vs. Long-Life Gear Oils

Gearboxes – differentials, transaxles, final drives – often face extreme pressures and shock loads, especially in towing, racing or off-road use. AMSOIL has developed specialized gear lubes that far exceed the performance of standard API GL-5 oils, protecting gears and bearings in the harshest conditions.

AMSOIL SEVERE GEAR® Synthetic Gear Lube is the top-tier gear oil line, available in popular viscosities like 75W-90, 75W-110, 75W-140, 80W-90, and even SAE 250 for racing. It is specifically engineered for severe-duty applications such as towing heavy trailers, 4x4 off-roading, racing differentials, and commercial equipment. Key benefits:

High Film Strength & Load Carrying: SEVERE GEAR uses an advanced extreme-pressure (EP) additive system (with proprietary “iron-sulfide” anti-wear film formation on gear surfaces) to handle shock loads and prevent scoring and pitting of gear teeth[68][69]. It exceeds the load stage requirements of ASTM and OEM tests. In practice, this means even under heavy torque or instantaneous shock (like wheel hop or launches), the oil maintains a lubricant film that cushions metal surfaces. It helps prevent “shock loading” failures and gear rashing that lesser oils might allow. Many users note that gear teeth and bearings show markedly less wear and polishing when using SEVERE GEAR, even after extended service.
Thermal Stability – Controls “Thermal Runaway”: In differentials, especially towing or racing, a phenomenon called thermal runaway can occur – heat from friction thins the oil, causing more friction and even more heat, potentially leading to gear oil foaming and failure. SEVERE GEAR is formulated to prevent thermal runaway[70]. It resists breakdown at high temps, and its friction modifiers actually reduce friction between gear teeth. By limiting excessive friction, it helps reduce operating temperatures. It also contains no wax (as it’s fully synthetic), which improves its high-temp stability and also benefits cold flow[71][72]. The result is a gear lube that can handle diff temps of 200-300°F without losing its protective properties or causing runaway heat buildup.
Extreme-Temperature Performance: This gear oil truly excels in both hot and cold extremes. In heat, it resists oxidation and prevents varnish and carbon deposits on gear surfaces[73][74]. Clean gears run cooler and more efficiently. In frigid conditions, SEVERE GEAR’s synthetic formulation and lack of paraffins mean it flows readily – enabling easier cold starts and less drag on the drivetrain until it warms. This can noticeably improve fuel economy and responsiveness in cold climates. For example, AMSOIL 75W-90 SEVERE GEAR has a pour point around -50°F, far lower than many conventional 80W-90 oils. So whether you’re in a desert towing up a grade, or driving on sub-zero winter mornings, SEVERE GEAR maintains optimal viscosity.
Seal and Component Life: SEVERE GEAR is formulated for long oil, seal, and equipment life[75]. It contains additives that condition seals to prevent leaks. It also has excellent compatibility with bronze synchros and other soft metals (in manual transaxles, for example). The fluid’s stability prevents the formation of acids that could attack seals or components. Additionally, its EP additives protect bearings and gear teeth so well that wear metals stay extremely low, preventing abrasive damage. Many enthusiasts report that after switching to SEVERE GEAR, the amount of metal “fuzz” on magnetic diff drain plugs is greatly reduced[76][77] – evidence of less wear.
Limited-Slip Performance: All SEVERE GEAR viscosities come pre-formulated with limited-slip friction modifiers[78]. This means smooth operation in clutch-type limited slip differentials – chatter or stick-slip is minimized without needing additional modifier additive (though it’s compatible with extra additive if a very sensitive LS unit requires fine-tuning). Most users find SEVERE GEAR provides smooth yet responsive LSD engagement.

SEVERE GEAR is recommended wherever an API GL-5 or MT-1 gear oil is called for, and it also covers SAE J2360 and various OEM specs. It’s suitable for high-performance cars, 4WD trucks, heavy equipment final drives, marine gearcases, etc. It is a favorite in off-road racing and rock crawling due to its ability to cling to gears (high adhesion/cohesion) and not fling off[79][80]. In fact, AMSOIL describes its adhesion as “tenacious” – it stays put on gears even when subjected to centrifugal force, ensuring that upon startup after a long drive, the gear surfaces are still coated.

AMSOIL Long Life Synthetic Gear Lube (available in 75W-90 and 80W-140) is an extended-drain gear oil formulated more for over-the-road trucks and long-haul commercial use (though also great for passenger vehicles). Its emphasis is on longevity and 500,000-mile drain intervals in heavy-duty trucks[81]. Key points:

Extraordinarily Long Service Life: Long Life gear oil is engineered to last several times longer than conventional gear oils, up to 500k miles in over-the-road trucks (per OEM drain specs)[81]. It meets requirements of Eaton/Roadranger, Meritor, and other axle makers for extended drains. This oil’s additive system is optimized to not deplete quickly – it maintains corrosion protection and EP protection over many years and hundreds of thousands of miles. By using Long Life, fleets can dramatically reduce the frequency of diff oil changes (which are often labor-intensive). Even in passenger cars or 4x4s, it provides “fill-for-life” performance – you could run it 100k+ miles with confidence (though checking level and condition periodically is prudent).
Outstanding Wear Protection: Despite being optimized for longevity, it doesn’t skimp on wear control. It uses shear-stable synthetic base oils and top-tier additives to form a durable protective film on metal[82][83]. This film and its EP additives guard against scoring and pitting under heavy loads, just like SEVERE GEAR. It also resists viscosity loss due to mechanical shear (gears churning the oil) so that even after many miles, it stays in grade and continues to protect.
Improved Efficiency: Long Life 75W-90 has inherently lower friction than thicker oils or conventional 85W-140s, etc. It also has a high VI and excellent cold-flow, which reduces drag at startup and in cold weather[84][85]. The result is less energy lost to friction – maximizing fuel economy. By running this in class 8 trucks, fleets can see a small bump in MPG (which adds up over hundreds of thousands of miles). It also keeps diffs running cooler under load. Furthermore, its advanced additive “MAXIMUM efficiency” claim includes preventing deposits that could impede heat transfer – it resists acids and varnish so cooling remains effective[86].
Anti-Rust, Anti-Corrosion, Anti-Foam: Long Life gear oil protects stored or infrequently used equipment as well. It conditions seals, prevents rust during downtime, and has anti-foam agents to keep the lubricant film intact (foam can collapse and cause metal contact). The all-season formulation means one oil can be used year-round without seasonal changes[87]. It’s recommended for everything from line-haul trucks to buses to heavy machinery – anywhere extended service and reliability are paramount[88].
Compatibility: It’s compatible with other brands/colors of gear oil, so topping up or mixing during transition isn’t harmful (though for best results, a full change is recommended). It is also safe on yellow metals (brass synchronizers, etc.). Note that Long Life does not contain limited-slip friction modifier – since it’s targeted at axles in big rigs (which usually have driver-controlled lockers or no LS clutches). If used in a passenger car LSD, one would add friction modifier as needed.

In summary, SEVERE GEAR vs. Long Life comes down to application focus: SEVERE GEAR is the choice for ultimate protection under extreme loads and shock, especially in consumer or racing scenarios, or off-road where you might change fluid more frequently due to water crossings, etc. Long Life is the choice for ultimate longevity and extended drain intervals, mainly for commercial/fleet use, or anyone who wants to “fill it and forget it” for a very long time. Both will protect your gears far better than standard gear lubes – preventing costly ring & pinion failures, reducing howling or whining (because gear surfaces stay smooth), and even improving fuel efficiency. They also both provide robust corrosion protection to gears and bearings, which is an often overlooked benefit – AMSOIL gear lubes virtually eliminate rust or etching on gear surfaces in humidity or idle periods[89][82].

Transmission Fluids: Precision Protection for Modern Transmissions (ATF, CVT, DCT)

Transmissions – whether automatic, continuously variable, or dual-clutch – have unique lubrication needs: clutch friction control, heat dissipation, wear protection for gears and bearings, and in automatics, valve-body and torque-converter performance. AMSOIL’s transmission fluids are fully synthetic, multi-functional, and built to outperform OEM fluids, often extending the life of the transmission and the fluid itself.

Automatic Transmission Fluids (ATF)

Signature Series Multi-Vehicle Synthetic ATF: This is AMSOIL’s premium ATF designed to cover a wide range of automatic transmissions (domestic and import) requiring Dexron® III, Mercon® V, SP, Toyota T-IV/WS, Honda Z-1, ATF+4, etc. It uses an advanced friction modifier system for proper clutch engagement across various transmission designs. Notable features:

Double the Severe-Service Interval: AMSOIL ATF handles heat so well that you can confidently double the vehicle manufacturer’s severe-service drain interval (with a warranty to back it)[90]. For example, if your truck says change ATF every 30,000 miles when towing, AMSOIL ATF is tested and guaranteed for 60,000 miles under those conditions[90]. This is thanks to its robust additive package (anti-oxidants, anti-wear, anti-foam) and high-purity synthetic base oils that don’t break down or oxidize like conventional ATFs.
Resistance to Oxidation & Sludge: Automatic transmissions run hot (some over 200°F) which can oxidize fluid and form varnish that sticks valves and clutches. In a 180,000-mile severe-service test, AMSOIL ATF retained 83% of its original oxidation inhibitors – still actively fighting fluid breakdown at the end of the test[91]. Inspecting the transmission afterward showed valve bodies virtually sludge-free and clutches with only trace discoloration (rated “good” as the highest level)[92][93]. This indicates AMSOIL ATF keeps transmissions exceptionally clean, ensuring valves and solenoids operate freely and clutches apply smoothly even after long use.
Heat Transfer and Cooling: AMSOIL ATF’s synthetic nature improves heat transfer compared to mineral ATFs. It also has a high viscosity index, so it stays thinner at very high temps, which aids cooler operation. Additionally, its anti-foam agents prevent foam (entrained air) that can impede cooling and lubricating. Many users note that transmissions run ~20-30°F cooler with AMSOIL, especially in towing or performance use. By controlling operating temperature, it reduces the chance of overheating and fluid degradation (heat is the #1 enemy of ATF).
Friction Durability & Smooth Shifts: Perhaps most critically, AMSOIL’s ATF has outstanding frictional stability. The formulation is dialed in so that clutch packs engage firmly without slip but without shudder. Over time, oxidation byproducts can alter a fluid’s friction characteristics – but AMSOIL ATF’s thermal stability ensures consistent “like-new” shifting feel even after tens of thousands of miles[94]. It prevents clutch glaze and glazing-related elongated shift times[94]. In other words, your 100,000-mile transmission can still shift crisp and quick as if the fluid were new. This friction durability extends the life of the clutch material itself as well (less heat and slip on clutch surfaces).
Cold-Temperature Performance: Thanks to its wax-free synthetic base, AMSOIL ATF flows readily in extreme cold[95]. It does not thicken up like conventional fluids that contain paraffin. This means faster engagement of gears in cold start and immediate hydraulic pressure for clutches. Solenoids and small valves function properly even at sub-zero because the fluid isn’t congealed. AMSOIL ATF’s pour point can be around -60°F, making it ideal for cold climates. Quick flow also reduces wear on clutches and bushings during cold starts, when fluid delay can otherwise cause momentary slippage or low pressure.
Multi-Vehicle Compatibility: It’s truly multi-vehicle – it meets or exceeds the requirements for a huge array of ATF specs (older Dex/Mercon to newer low-viscosity ATF specs). AMSOIL publishes compatibility lists, and it’s safe in virtually any 4-, 5-, 6-, 8-speed automatics that call for a conventional ATF. (They also have a separate low-viscosity ATF if needed for certain 8+ speed transmissions that require an ultra-low viscosity fluid, but for many, this Multi-Vehicle ATF suffices.) Using one fluid for an entire fleet simplifies maintenance and reduces risk of misapplication. Importantly, it’s compatible with OEM fluids, so it can be used for top-off or full flush. No issues mixing with remnants of factory fluid during a pan drain.

One example of its performance: In a fleet of taxi cabs, a test of AMSOIL ATF vs. a leading OEM ATF showed AMSOIL fluid kept transmissions cleaner and shift quality higher over the same mileage. AMSOIL also offers a Torque-Drive® ATF (discussed next) for Allison and other heavy-duty uses, but for most cars/trucks, Signature Series Multi-Vehicle ATF is the top choice.

AMSOIL Torque-Drive® Synthetic ATF: This is a specialized ATF originally formulated to meet Allison TES-295 spec (heavy-duty automatics in commercial trucks, buses, etc.). It’s effectively a replacement for Allison Transynd® fluid, and also works in any application requiring a high-performance Dexron III/Mercon. Torque-Drive is noteworthy because:

It is highly robust for severe, continuous operation – ideal for fleet automatics that see extreme heat or extended drains. It can often go 100,000+ miles in service in heavy trucks (following OEM extended drain guidelines). It eliminates the deficiencies of petroleum ATFs, offering far superior resistance to thermal and oxidative degradation, sludge, varnish, viscosity breakdown, etc.[96].
It’s a multi-functional fluid for mixed fleets – aside from Allison transmissions, it covers Voith, ZF, CAT, MB, and many others (listed in its specs)[97]. A municipality or fleet can stock AMSOIL Torque-Drive and use it in fire trucks, buses, utility trucks, etc., wherever a tough ATF is needed – simplifying inventory.
Wear Control: Severe-service automatics (like in dump trucks or frequent-stop buses) generate a lot of heat and shearing forces. Torque-Drive has top-of-the-line anti-wear additives and high film strength to prevent metal-to-metal contact in things like planetary gear sets and bushings[98][99]. By maintaining viscosity and additive integrity, it protects gear trains and bearings for much longer than standard ATF. Users often report transmissions lasting significantly longer between rebuilds when using Torque-Drive.
Friction and Clutch Life: It ensures consistent, smooth clutch engagement in heavy-duty applications throughout the fluid life[94]. Clutch packs in heavy autos are sensitive to fluid frictional properties – Torque-Drive’s oxidation stability means it does not allow the friction characteristics to deteriorate quickly. Thus shift quality and clutch holding capacity remain stable. No glazing, no shudder, even after long, hard service[94]. This extends the life of clutch material. By contrast, conventional ATF can oxidize and cause clutch plates to grab or slip erratically over time.
Extreme Temp Performance: Hot: It significantly slows oxidation, preventing sludge that can block valves and varnish that can stick solenoids[100]. Cold: It flows when cold because it lacks wax, so it supports proper function of finely controlled solenoids and clutches even in freezing weather[101]. An Allison transmission with Torque-Drive will respond quickly on a cold morning without the “morning sickness” of delayed shifts that some fluids exhibit.

Torque-Drive is recommended where an Allison TES-295 fluid is required (e.g. Allison 1000/2000/3000 series transmissions in pickups or RVs). It’s also perfect for older classic car automatics that run hot or where you want maximum longevity (for instance, someone might use it in a classic TH400 drag racing transmission to ensure stable performance run after run).

Result of Using AMSOIL ATFs: Transmissions run cooler, shift more consistently, and simply last longer. Fluids don’t need to be changed as often – e.g., some users do a pan drop every ~50k miles with AMSOIL ATF and consistently find the fluid still red and fresh-smelling, whereas with OEM fluid it might be brown and burnt by then. The improved lubricity can also yield a slight uptick in fuel economy (less drag in the torque converter and pump). Importantly, the confidence in no sudden failures is key – AMSOIL ATF resists the thermal runaway that can lead to sudden fluid burnout and loss of function. It’s a cheap insurance for transmissions that cost thousands to rebuild.

Specialized Transmission Fluids: CVT & DCT

Modern vehicles increasingly use CVT (Continuously Variable Transmissions) and DCT (Dual-Clutch Transmissions), each requiring unique fluid characteristics. AMSOIL offers dedicated fluids for each:

AMSOIL Synthetic CVT Fluid: Formulated for belt- and chain-type CVTs found in many cars and powersports. CVTs rely on a specific friction profile – the fluid must allow the steel belt or chain to grip the pulleys firmly without slip (to transfer torque), yet also lubricate the pulley surfaces and any conventional gears. Highlights:

Prevents Belt/Chain Slip: AMSOIL CVT fluid provides outstanding metal-to-metal frictional properties designed specifically so the CVT’s belt or chain remains in contact without slipping[102][103]. This is crucial – any slip leads to belt/pulley wear and a loss of drive. AMSOIL’s fluid uses friction modifiers that create the right level of friction – not too high (which could cause shudder or inefficiency) and not too low (which would allow slip). It’s tuned to maximize power transmission through the CVT.
High-Film Strength & Wear Protection: CVTs have not only the belt and pulleys but also support bearings and often a reduction gearset and differential. AMSOIL CVT fluid is durable under pressure, effectively resisting wear on critical parts[104][105]. It helps prevent wear even in severe service (like a small engine pushing a heavy car, or prolonged high-speed operation). By protecting against metal-to-metal contact, it extends the life of the CVT unit.
Prevents Varnish and Glazing: CVTs can run hot, which can cause lesser fluids to form varnish on pulley surfaces or gum up control valves. AMSOIL CVT’s synthetic formulation is thermally stable – it guards against the heat-induced breakdown that causes deposits[106]. Pulleys stay clean, which is important for the belt’s grip. It also resists oxidation that could thicken the fluid or alter its friction over time.
Anti-Shudder and Smooth Operation: Many CVTs use a wet clutch pack for forward/reverse or a torque converter clutch. AMSOIL CVT fluid provides superior wet-clutch performance, giving outstanding anti-shudder durability and reducing vibrations[107]. This means smoother acceleration without the “chatter” or “judder” that sometimes plagues CVTs as fluid ages. It keeps the drive feeling seamless and consistent.
Field Proven in Severe Use: AMSOIL tested this fluid in Las Vegas taxi CVTs – four taxis, 100,000 miles each in extreme heat and constant use. The result: outstanding protection – belts and CVT components showed minimal wear and continued performance[108]. That’s a torture test for CVTs, and AMSOIL passed with flying colors. Customers using it in personal vehicles often report improved shift response and longevity (some belt-driven ATV/UTV transmissions also benefit from a quality CVT fluid like this).

This CVT fluid is compatible with common CVT specs (Nissan NS-2/NS-3, Mitsubishi, Toyota CVT, Honda HCF-2, Hyundai/Kia, Subaru, etc.). Using it can solve or prevent belt slip codes and extend the interval between CVT fluid changes. Considering how expensive CVT repairs are, fluid quality is critical – and AMSOIL delivers maximum protection to keep that transmission alive.

AMSOIL Synthetic DCT (Dual-Clutch Transmission) Fluid: Designed for the high-tech dual-clutch gearboxes in many performance cars (VW/Audi DSG, BMW DCT, Porsche PDK, Ford/Getrag dual-clutch units, etc.). DCTs essentially combine manual transmission gears with automated dual wet clutches. The fluid must perform as both gear oil (protect gears/bearings) and ATF (enable clutch engagement and hydraulic actuation). AMSOIL DCT fluid excels by:

Preventing Shudder & Ensuring Fast Shifts: It has perfectly balanced frictional properties to prevent clutch shudder and facilitate lightning-quick, smooth shifts[109][110]. In DCTs, if friction is too high or too low, you’ll get jerky shifts or slipping. AMSOIL engineered this fluid to consistently provide the right friction so that clutches bite firmly but release cleanly. The result is fast, crisp shifts under all conditions. Drivers notice that gear changes remain quick and seamless, as the fluid maintains the intended friction characteristics over time.
Outstanding Wear Protection for Gears & Bearings: DCTs have complex gear trains (often more gears than a standard manual due to two sub-transmissions). AMSOIL DCT uses high film-strength synthetic base oils plus anti-wear/extreme-pressure additives to shield gears, bearings and synchronizers from wear[111]. It resists the shearing forces of high torque and high RPM, preventing metal-to-metal contact even in hard use. Additionally, resisting extreme heat is crucial in track use – AMSOIL DCT maintains viscosity and doesn’t thin excessively at high temp, preserving the oil film on components[112].
Resists Heat & Oxidation: DCTs can generate heat especially in urban driving (constant clutch engagements) or track use. This fluid maintains proper viscosity at extreme temperatures to ensure adequate protection during the most intense conditions (like a dual-clutch supercar on a hot track)[113]. It’s formulated to withstand the high temperatures without oxidizing into sludge or varnish that could impede the delicate solenoids and valves that control clutch actuation. So, it supports consistent performance even when pushed to the limit.
Shear-Stable for Consistent Performance: With high-horsepower, high-torque applications, some fluids can shear down and lose viscosity. AMSOIL DCT boasts superior shear stability – it resists viscosity loss under extreme stress[114]. That means even after hard use, it remains in the correct viscosity grade to cushion gear teeth and maintain hydraulic pressure. This stability is one reason it can lengthen the service life in DCTs, potentially doubling the change interval versus lesser fluids (though always follow warranty requirements).
Compatibility & Protection: It’s safe for all common dual-clutch transmission materials and meets specifications for numerous makes (BMW, VW/Audi, Porsche, Ford, Mercedes, etc.)[115][116]. It’s a true multi-spec fluid. It also contains strong corrosion inhibitors to protect delicate components from any moisture ingress or acid formation[113]. For high-performance driving, one big benefit is that it works equally well as a race fluid with straight water-cooled systems – meaning if someone runs a DCT cooler or such, the fluid still protects.

Owners who switch to AMSOIL DCT fluid often note improved shift quality and clutch behavior, especially if the factory fill was starting to degrade. It can cure slight shudders or slow shifts by refreshing the frictional properties. For track enthusiasts, it provides peace of mind that the fluid will hold up session after session without causing a gearbox failure or needing overly frequent changes.

Summing Up Transmission Fluids:

With AMSOIL fluids, your transmission (automatic, CVT, or DCT) gets a fluid that exceeds OEM requirements for film strength, oxidation resistance, and friction control. This means:

· Clutches (whether in automatics or DCTs) last longer and perform consistently (no glaze, no chatter).

· Gears and bushings see minimal wear, extending transmission life.

· Fluid doesn’t have to be changed as often, saving money and preventing downtime.

· Cooler operation under load, which can prevent catastrophic overheating scenarios.

· Smoother operation – which you feel as a driver in the form of crisp shifts and responsive engagement, even as the miles add up.

Transmissions are some of the most expensive components to repair or replace, so using a premium fluid is cheap insurance. AMSOIL’s track record in transmissions – from drag racers shaving fractions off ETs to fleet vehicles running hundreds of thousands of trouble-free miles – demonstrates their commitment to protecting these complex machines.

Greases: Unbeatable Adhesion and Load Protection

When it comes to grease, the goal is to stay in place under pressure and provide continuous protection. AMSOIL’s synthetic greases are engineered to handle extreme pressures, impacts, water washout, and high temperatures far beyond conventional greases. Three standouts are Synthetic Polymeric Off-Road Grease, Synthetic Multi-Purpose Grease, and DOMINATOR® Racing Grease – each formulated for specific demands but all featuring AMSOIL’s hallmark of extended service and top-tier protection.

AMSOIL Synthetic Polymeric Off-Road Grease (available in NLGI #1 and #2, with moly) – This is a specialty grease designed for heavy equipment in punishing conditions: think construction and farm machinery pivot pins, chassis points on dozers and loaders, heavy trailer hitch pivots, etc. What makes it special:

Extraordinary Adhesion & Cohesion: This grease contains a proprietary polymer that gives it exceptional stickiness (cling to metal) and internal cohesion (cling to itself)[117][79]. In heavily loaded pins and bushings, many greases get pounded out (squeeze-out) or sling off – leaving surfaces unprotected. The Polymeric Off-Road Grease stays in place much longer, even under repeated shock loading and pounding[79][80]. It literally forms a tenacious film that won’t easily be knocked out by the impact of, say, a loader bucket jarring or a chassis pivot under heavy load. This greatly extends re-greasing intervals.
Fortified with 5% Molybdenum Disulfide: Moly provides an extra solid-film layer of wear protection for slow, heavy sliding motions (like pin joints). AMSOIL off-road grease is heavily fortified with moly for maximum wear protection in these extreme-pressure, low-speed contact zones[118][119]. Even if the grease film is momentarily pushed aside, the moly plating on surfaces prevents metal-to-metal contact – preventing galling and extending component life drastically.
Resists Impact & “Pound-Out”: This grease is literally formulated to resist impact better than others and stay in place longer[79]. In lab tests that simulate pounding action, it doesn’t splatter out or break down. AMSOIL’s polymer technology keeps the grease between surfaces, meaning parts like loader pin bushings or excavator bucket pins are continuously lubricated, not intermittently dry. This prolongs equipment life (those pins and bushings are expensive to replace and difficult to press out/in). Users often find that where they used to grease daily, with AMSOIL Polymeric they can grease weekly with no increase in wear.
Water Washout Resistance: Off-road equipment often faces water (rain, mud, pressure washing). This grease has excellent resistance to water washout, helping it maintain a seal on greased components and keep water/contaminants out[80][120]. It won’t emulsify and run off easily like some soaps-based greases. This is crucial for things like excavator pins that are exposed to mud – AMSOIL grease keeps water from entering and causing rust or abrasive slurry inside the joint.
Extended Service & Reduced Consumption: Because it stays put and doesn’t need replacement as often, it allows extended greasing intervals and reduced grease consumption[121][122]. AMSOIL specifically notes that it reduces the amount of grease ejected during repetitive pounding, so less mess and waste[122]. Over time, using this grease can save money simply by using less grease and reducing labor (less frequent greasing). Also, fewer worn-out pins to service.

In sum, AMSOIL Polymeric Off-Road Grease is ideal for heavy-duty pins, bushings, chassis lube points, wheel loader joints, articulated truck pivots, etc. under extreme load. It meets Caterpillar’s requirement for 5% moly in pin/bushing grease. People who use it report far less wear upon tear-down – for example, one might find “shiny like new” pin surfaces instead of the brinelled, worn look they might expect. It truly sticks like tar (in a good way) to the parts. Even under water or mud, it stays and keeps protecting.

AMSOIL Synthetic Multi-Purpose Grease (NLGI #2, GC-LB) – This grease is the general-purpose superstar, suitable for automotive wheel bearings, chassis, U-joints, farm equipment, and industrial bearings. It uses a Calcium-Sulfonate Complex thickener (one of the best thickeners available, known for inherent corrosion protection and high drop point). Its benefits:

Excellent High-Temperature Performance: The calcium-sulfonate complex thickener gives it a very high dropping point (the temp at which grease melts) – typically over 500°F. Combined with synthetic base oils, this means it resists thinning or running at continuous high temps (like in disc brake wheel bearings). It also resists thermal/oxidative degradation for long-term performance[123][124]. Even in heavy braking or high-speed conditions, it won’t carbonize or harden like some lithium greases can.
Outstanding Load Carrying & EP Protection: This Multi-Purpose grease has excellent film strength and EP additives, handling heavy and shock loads in both low- and high-speed bearings[125][126]. It’s rated GC-LB, meaning it meets the highest standards for wheel bearing (GC) and chassis (LB) use. In wear tests, it prevents scarring of bearings under high loads. For example, in test rigs for bearing wear (like ASTM D2596 weld point), it scores very high, indicating robust EP performance.
Adhesive and Shear-Stable: AMSOIL Multi-Purpose is formulated to be adhesive (sticks to metal) and shear-stable (doesn’t break down under mechanical stress)[123][127]. This prevents it from being squeezed out of joints or thrown off at high rotation. In wheel bearings or U-joints, it stays in place to do its job, rather than thinning out and leaking. Its mechanical stability means after long service, it hasn’t significantly altered consistency – it still provides a cushioning layer.
Water Resistance & Corrosion Protection: Calcium-sulfonate greases are known for superior inherent corrosion inhibition – AMSOIL’s grease capitalizes on this, virtually eliminating rust on greased parts[128][129]. It also has excellent water-washout resistance, making it great for boats, ATVs, or frequent rain exposure[129]. It won’t easily wash off, and it actively protects metal if water is present. This is a big advantage in, say, trailer wheel bearings that might be submerged during boat launching – the grease keeps bearings protected from salt/fresh water.
All-Weather Performance: With a broad operating temperature range, this grease stays pliable in extreme cold (thanks to the synthetic base oils with low pour point)[123][130], and doesn’t excessively soften in heat. Its low-temperature torque values are excellent – meaning it allows bearings to rotate freely in cold conditions without excessive resistance[131]. So your car’s wheel bearings or an electric motor in a freezer environment can run smoothly. And in blazing heat, it’s not going to leak out of a bearing cap.
Long Service Life: Because it resists oxidation and maintains consistency, AMSOIL Multi-Purpose can extend relubrication intervals in many cases. For example, in passenger vehicle wheel bearings, it can easily last the recommended interval or beyond with no issues. In fleet service, it might allow longer intervals between greasing chassis points, reducing maintenance.

It’s basically an upgrade over lithium-complex greases in almost every aspect – better high-temp, better corrosion protection, better water resistance. Users often see improvements like reduced wear on ball joints or longer life out of trailer bearings. It’s truly a “do-it-all” grease for automotive and light-industrial use. (It’s not intended for constant extreme shock loads – that’s what the Polymeric Off-Road Grease is for – but it handles moderate shock and heavy loads very well.)

AMSOIL DOMINATOR® Synthetic Racing Grease (NLGI #2) – This is a specialty grease aimed at high-speed, high-temperature, and high-impact racing applications (though it’s useful for any performance use). It uses a Calcium-Sulfonate Complex thickener as well, and is loaded with extreme-pressure additives. Standout features:

High-Speed/High-Temp Capability: Racing wheel bearings (e.g. stock car wheel hubs, off-road truck hubs, motorcycle axles) can see extreme speeds and heat. DOMINATOR Grease has exceptional mechanical stability so it won’t soften or fling out at high RPM[132][133]. It’s designed to handle the heat of racing brakes and the high G-forces on the grease in, say, a NASCAR wheel bearing. The grease lasts longer and continues to protect where conventional greases would liquefy or harden. It also has a high dropping point, so it stays in place even as temps approach 500°F.
Reduced Friction = More Power: This grease contains friction modifiers that lower friction in the bearing[134][135]. By reducing friction, it maximizes power throughput and efficiency[135]. In racing, that can mean a bit less rolling resistance from wheel bearings or driveline components, potentially translating to a measurable performance edge. Lower friction also means less heat generated in the bearing, which can be crucial in endurance events.
Outstanding EP Wear Protection: Under heavily loaded, high-speed conditions, DOMINATOR Grease’s EP package provides excellent wear protection[136][137]. It prevents spalling or pitting of bearings despite the stress of cornering loads or jumps (in off-road racing). It’s formulated to handle both high-speed low-torque and low-speed high-torque situations – which is unique. It will protect a slow-moving, heavily loaded suspension bushing and a high-speed wheel bearing equally well[138][139]. It truly has the load-bearing capacity of a heavy-duty grease and the consistency needed for high-speed bearings.
All-Weather (Racing) Use: It flows well in cold, and remains consistent in heat – giving a racer confidence that whether it’s a cold start or a heated end-of-race condition, the grease is still doing its job. It also resists water and mud notably well for a racing grease – off-road trucks that get components wet won’t immediately lose lubrication.
Corrosion Protection: Racing vehicles often sit for periods between events – DOMINATOR Grease has robust anti-corrosion ingredients to protect metals during storage or humidity[140]. For example, if a race car sits in the shop for weeks, the grease in the bearings will prevent rust much better than a basic grease. It’s also excellent for any application using straight water as coolant (like some drag cars use water in block) – if used in pumps etc., it resists rust in presence of water.

In essence, DOMINATOR Racing Grease gives racing components the best chance at survival under extreme conditions. For instance, off-road race trucks landing jumps often break parts – but with this grease, at least the lubrication is not the weak link. Similarly, track cars pushing their wheel bearings to the limit get extended life. Many racing teams use it in suspension pivots, u-joints, ball joints, and wheel bearings for an edge in durability and efficiency. It’s also suitable for powersports (ATV racing, snowmobiles) and even high-performance street vehicles where you want the ultimate grease.

Grease Summary:

Choosing the right AMSOIL grease depends on the application:

Polymeric Off-Road Grease: Use for slow-moving, extremely loaded joints (construction equipment, heavy farm machinery, off-road chassis points). It’s all about adhesion and shock load – it will not pound out. Contains moly for sliding surfaces.
Multi-Purpose Grease: The go-to for most vehicles and machinery – wheel bearings, U-joints, ball joints, industrial bearings, even electric motor bearings. It’s long-life, waterproof, and high-performance across the board (and GC-LB certified).
DOMINATOR Racing Grease: Use where extreme speeds or temps meet high loads – racing, powersports, or performance street use. It reduces friction and stands up to racing abuse, while still protecting like a heavy-duty grease.

All AMSOIL greases share the benefit of extended service intervals and better protection than conventional greases, meaning less downtime for re-lubrication and less component replacement. Users frequently remark on things like “no more squeaky joints,” “bearings run cooler,” or “grease still looked good after a season of hard use.” In fleet scenarios, greasing intervals can often be doubled, saving labor. And because they’re synthetic, they often have a broader usable temperature range, especially on the cold end, which can be important for greased machinery operating year-round in varying climates.

2-Stroke and 4-Stroke Specialty Oils: SABER®, INTERCEPTOR®, HP Marine® and More

AMSOIL’s expertise isn’t limited to automotive fluids – they are also a leader in small engine and powersports lubrication, including 2-stroke (premix and injector) oils and high-performance 4-stroke oils for motorcycles, ATVs, marine, and more. These engines often face high RPM, high heat, and in the case of 2-strokes, need oil to burn cleanly. AMSOIL’s synthetic formulations deliver exceptional performance, often solving problems like plug fouling, exhaust port clogging, and ring sticking that plague lesser oils.

AMSOIL SABER® Professional 100:1 Synthetic 2-Stroke Oil: This is a unique premix oil that is so high performance it can be safely run at 100:1 mix ratios (though it’s also effective at richer ratios) in equipment that typically calls for 50:1 or 80:1. It’s targeted at small 2-stroke equipment like string trimmers, leaf blowers, chainsaws, etc., and also popular in powersports (some use it in dirt bikes or older motorcycles).

Ultra-Clean Combustion: SABER’s synthetic formulation and additive package result in remarkably clean burning. It produces far fewer carbon deposits than conventional 2-stroke oils. In testing, equipment run with SABER at 100:1 was 96% carbon-free in the exhaust port and spark arrestor screens[141][142] – essentially no significant carbon deposits, whereas other oils at 50:1 left heavy carbon. This has huge real-world impact: no stuck piston rings, no clogged exhaust ports, no fouled spark plugs, and maintained compression and power[143]. Even at the lean 100:1 mix, SABER outperformed other oils mixed at 50:1 in terms of cleanliness[144]. That indicates how well it burns and lubricates with minimal residue.
High Detergency – Fights Power-Robbing Deposits: SABER contains high-quality detergents that actively eliminate existing carbon deposits and prevent new ones. So switching to SABER can actually clean up an engine previously run on dirty oil. By keeping the piston crown and ring grooves clean, it ensures rings can seal properly and the engine maintains compression and horsepower. It “fights power-robbing carbon” effectively[144].
Superior Lubricity (Even at 100:1): One might worry that 100:1 doesn’t provide enough oil – but SABER’s advanced chemistry provides ample lubricity and film strength at that ratio, protecting bearings and cylinder walls fully. In fact, because it burns so clean, it often protects better than a dirty 50:1 mix that might cause ring sticking or abrasive deposits. AMSOIL’s confidence is such that using SABER at 100:1 cuts oil costs by 50% or more versus 50:1, while still delivering excellent protection[145]. That’s a huge cost and convenience benefit for commercial landscapers or anyone running lots of 2-stroke equipment – half the oil usage with no sacrifice (and likely gains) in engine life.
Reduced Smoke and Odor: Running SABER, especially at leaner mix, produces noticeably less blue smoke and less exhaust odor, since the oil is mostly combusted. Operators appreciate this when using blowers or saws for hours. It also means less carbon buildup in spark arrestor screens (preventing those annoying clogs that kill power or cause stalling).
Fuel Stabilization: SABER Professional even includes a fuel stabilizer to help prevent fuel breakdown in equipment that sits[146]. This is a great bonus – ethanol-containing gas can go stale or form gums in carburetors; SABER helps mitigate that, keeping small engines running reliably (especially useful for seasonal equipment).
Versatility: It’s recommended for all handheld 2-stroke equipment and any pre-mix application (JASO FD, ISO-L-EGD, API TC). So one oil can cover your chainsaw, your outboard (SABER is available in a “Marine” variant too, but fundamentally similar), your gas-powered trimmer, etc. No need for multiple mix oils for different equipment.

Users of SABER often find their equipment runs cooler and gains a little performance – throttle response can improve because the engine isn’t bogged by heavy oils. Plus, less plug fouling means fewer maintenance interruptions. The ability to run 100:1 safely also means if you have a mix can for 50:1, you could effectively double the amount of fuel from the same oil volume – carrying less oil bottles into the field.

AMSOIL INTERCEPTOR® Synthetic 2-Stroke Oil: This is formulated for high-performance powersports 2-stroke engines, particularly snowmobiles, personal watercraft, dirt bikes, etc., including those with exhaust power valves. It’s designed to be used in oil injection systems or premix at 50:1, and it shines in applications like Ski-Doo® E-TEC engines, where it meets/exceeds the OEM spec. Key characteristics:

Preventing Ring Sticking & Power Valve Deposits: INTERCEPTOR is known for outstanding cleanliness in the combustion chamber and exhaust power valve areas. Its synthetic formulation resists deposit formation and it is fortified with high-temp detergents/dispersants to actively keep surfaces clean[147][148]. Ski-Doo E-TEC engines, for example, have electronically controlled exhaust valves that can stick if the oil deposits carbon – INTERCEPTOR prevents exhaust valve sticking, ensuring maximum power and proper operation[148]. It also keeps piston rings free – preventing the compression loss and scuffing that can occur when rings get carboned up.
Excellent Wear Protection: Despite being low smoke and clean, it has great lubricity. It’s formulated to resist burn-off, meaning a higher percentage of the oil makes it through the combustion zone to lubricate the lower end and cylinder walls[149]. AMSOIL notes that because it resists burning, more oil is available to lubricate, providing a safety margin of protection[149]. It has excellent film strength to protect pistons from scuffing – even in high RPM, high load conditions (like sustained wide-open runs on a snowmobile across a lake).
Cold-Temperature Flow: Snowmobile engines often start in sub-zero conditions. INTERCEPTOR has an pour point of -63°F and remains fluid for injector pumps in extreme cold[150][151]. This ensures oil injection works immediately on cold start to protect the engine. It also prevents gelling in the lines or filter.
Low Smoke, Low Odor: It’s designed to burn as cleanly as possible in high-output engines, so riders get minimal smoke and smell. For example, a group riding 2-stroke snowmobiles with INTERCEPTOR will notice much less exhaust smoke than older mineral 2-stroke oils, which adds to riding enjoyment and reduces pollution.
Dyno-proven performance: AMSOIL’s torture test of INTERCEPTOR involved a 2016 Rotax E-TEC 800R (a very demanding direct-injected 2T). After 50 hours at WOT intervals, teardown showed zero ring sticking, very light piston wash (proper lubrication), and clean power valves. It indicates that INTERCEPTOR can handle the stresses of modern 2-strokes that push 160+ HP, without issues. AMSOIL is confident enough that they offer a Runs on Freedom® Warranty for snowmobiles using INTERCEPTOR – covering engine repairs up to 2 years/5,000 miles if the oil caused a failure[24] (an extra assurance of its protective ability).

In short, INTERCEPTOR is the go-to oil for recreational performance 2-strokes, especially where API TC or JASO FD oils are specified. Many sled and dirt bike owners find their exhaust power valves stay clean and functional season after season with minimal scraping, and top-end tear-downs reveal surprisingly clean pistons and combustion chambers. It’s also fairly economical in consumption – because it protects so well, some users find they can reduce the oil pump flow (where adjustable) slightly and still maintain protection (though one should be cautious doing so). Typically though, just using it in place of OEM oil yields fewer oil-related issues.

AMSOIL HP Marine® Synthetic 2-Stroke Oil: This is a premium oil for outboard motors and other marine 2-strokes, particularly direct-injection or E-Tec outboards, jet skis, etc. It’s made to handle continuous high load and to be “low aquatic toxicity” (biodegradable components) to minimize environmental impact. Key benefits:

Increased Lubricity, Even for Lean-Mix Settings: Some modern outboards (like Evinrude E-TEC) run extremely lean oil mixtures under computer control to reduce smoke. HP Marine is boosted with extra lubricity agents to fight piston and cylinder wear even during those lean-mix moments[152][153]. It prevents piston scuffing and ring sticking under these conditions, preserving engine life. It exceeds TC-W3 requirements easily, meaning it can be used in place of any OEM marine oil with better results.
Detergency for Continuous Operation: Marine engines can run full throttle for extended periods. HP Marine contains “MAXDOSE” additive system for super-clean operation[154]. It prevents piston-ring land deposits and exhaust port deposits that can accumulate during all-day trolling or high-speed runs[155]. This keeps performance consistent and avoids issues like rings sticking due to carbon. It’s designed such that even if you idle a lot (which can cause deposits normally), your engine remains clean.
Low Smoke & Low Toxicity: As a low-ash oil with biodegradable base components, it produces minimal smoke and has low toxicity to aquatic life[153][156]. This is important for environmental regulations and for the health of fisheries. If a bit of unburned oil gets into the water, it biodegrades more readily and is less harmful compared to conventional oils. Many users note less sheen on the water and less smoke at startup when using HP Marine compared to other TC-W3 oils.
Corrosion Protection: Marine engines face corrosion from saltwater exposure and intermittent use. HP Marine is formulated to protect against rust and corrosion of internal parts during storage or downtime[157]. It coats parts with a thin film that wards off moisture. This is crucial for outboards that might sit for weeks – the oil doesn’t strip off immediately and leave parts unprotected.
All-Purpose Marine: It’s recommended as injection or premix (50:1) for all two-stroke outboards (Yamaha, Mercury, Evinrude, etc.), as well as personal watercraft, jet boats, and even snowmobiles or ATVs where a TC-W3 or low-ash API TC oil is desired. (Though for snowmobiles, INTERCEPTOR might be better – but HP Marine can handle them, especially if someone wants one oil for both outboard and snowmobile in remote regions.)

Overall, HP Marine gives boaters peace of mind: whether trolling at low RPM (where spark plug fouling or carbon can be an issue) or blasting full throttle to a fishing spot, the oil performs flawlessly. Engines run smoother and with fewer hiccups, spark plugs stay cleaner (meaning fewer misfires and better fuel economy), and engine internals remain in near-new condition for many seasons. Many users have reported tear-downs of outboards after years of HP Marine use showing excellent compression and very clean pistons[158] – anecdotal evidence that aligns with AMSOIL’s claims of deposit control and wear protection.

Other 2-Stroke/4-Stroke Products: AMSOIL also offers DOMINATOR® Racing 2-Stroke Oil (for mix ratios used in racing – highly focused on extreme load/high RPM, with high film strength for pre-mix racing dirt bikes, etc.) and a line of 4-stroke powersports oils (like Synthetic ATV/UTV 10W-40, Synthetic Motorcycle oils in various viscosities, etc.). These 4-stroke oils also feature many of the benefits of the automotive oils – like high zinc for flat-tappet cam protection in bikes, or friction modifiers tuned for wet clutches in motorcycles.

For instance, AMSOIL’s Metric Motorcycle Oil 10W-40 or V-Twin 20W-50 are hugely popular – they reduce heat and wear in bikes, and in wet-clutch bikes, provide consistent clutch lock-up and smooth shifting. Similarly, AMSOIL ATV/UTV 4-Stroke Oils (we touched on earlier in the ATV/UTV section) are built to handle the high revs and severe service of off-road engines (often delivering reserve protection against heat and stable viscosity when engines are worked hard)[159][160].

In particular, AMSOIL’s ATV/UTV 5W-50 or 10W-40 oils have excellent resistance to viscosity breakdown from mechanical shearing in transmission gears (since many ATVs share engine and gearbox oil) and contain anti-foam and extra anti-wear additives for the severe combined engine/transmission environment. They keep those small, hot engines clean and protect even under mudding or heavy load (plowing, etc.) – where conventional oils might shear out of grade or oxidize quickly.

To wrap up: If you have a small engine or powersports equipment – from chainsaws and lawn mowers to snowmobiles, marine outboards, and dirt bikes – AMSOIL likely has a specific oil that will outperform the standard oil. The common theme is:

· Cleaner engines (less deposits, meaning maintained power and efficiency).

· Better wear protection (longer engine life, fewer seizures or top-end rebuilds).

· Often reduced emissions like smoke or plug fouling (which is both eco-friendly and performance-friendly).

· In many cases, longer mix oil life or less oil used (as with SABER 100:1 or simply oils that allow longer intervals between decarbonizing or rebuilds).

For professional landscapers, boaters, racers, or just enthusiasts who want the best for their equipment, the cost of these premium oils is justified by the reduced maintenance, downtime, and extended equipment lifespan. Spark plugs, piston rings, power valves – all stay cleaner and last longer. Engines produce designed power longer without rebuild. That’s the AMSOIL difference, applied to two-strokes and small engines.

Small Engine, Powersports, and Commercial Fluids: Tailored Solutions (Zero-Turn Hydrostatic, ATV/UTV, and More)

Beyond engine oils, AMSOIL addresses lubricants for small engine transmissions, hydrostatic drives, and other commercial equipment. A few notable products stand out:

AMSOIL 20W-50 Zero-Turn Synthetic Hydrostatic Transmission Fluid: This fluid is purpose-built for the hydrostatic transmissions in zero-turn mowers and other lawn/garden equipment. These hydrostats (like Hydro-Gear® units) often call for motor oil or a generic hydraulic oil – but they run hot and are subject to shearing, which can lead to speed loss or hydro pump wear. AMSOIL’s fluid offers:

High-Zinc Anti-Wear Protection: It’s a “high-zinc” formula that fights wear in hydrostatic pump and motor components (swash plates, hydraulic pistons, gears)[161][162]. The added zinc and phosphorus EP additives maintain a strong film on metal surfaces to prevent scoring under the immense pressures in hydro pumps. This prolongs the life of expensive hydro units.
Maintains Mower Speed & Responsiveness: As these fluids heat up, regular motor oils can thin out (losing hydraulic pressure) or shear down over time, causing the mower to creep slower or feel less responsive. AMSOIL’s fluid is purpose-built to resist viscosity loss in extreme heat, thus preserving proper oil pressure and motor-wheel torque so the mower doesn’t slow down when hot[162][163]. Operators get consistent ground speed and responsiveness, meaning productivity stays high even after hours of mowing on a hot day.
Shear-Stable & Oxidation Resistant: With continuous use, many motor oils shear (drop to a lower viscosity) in hydrostats and/or oxidize (forming sludge). AMSOIL’s hydrostatic fluid is extremely shear-stable and resists thermal breakdown, giving it a much longer service life[164][165]. It’s aimed at commercial operators who put hundreds of hours on mowers – they can trust the fluid for the whole season or more (AMSOIL suggests significantly extended drain intervals vs. OEM fluids). Clean fluid means less maintenance and longer hydrostatic unit life.
Reduces Wear and Temperatures: By forming a durable protective film and maintaining viscosity, it reduces internal leakage and wear. Less friction internally also means less heat generated – users often find their hydro units run cooler with AMSOIL, which further extends life (heat is a big killer of hydro pumps). Also, prevention of varnish means the fine tolerances in the pump remain clear, keeping efficiency up.
Commercial-Grade Reliability: It’s marketed to those who depend on their equipment to make a living – e.g. lawn care companies[166]. For them, a hydrostatic drive failure is downtime and big cost. AMSOIL fluid virtually eliminates hydro failures due to lubrication. It also meets or exceeds the specs of most hydrostatic transmissions (Hydro-Gear, Parker, etc.), so it can be used wherever 20W-50 (or often 15W-50/20W-50 motor oil) is recommended.

For a landscaper, switching to AMSOIL hydrostatic fluid typically results in smoother operation (less whine), steadier tracking, and the peace of mind that those expensive hydro pumps will go the distance. Some even report slight fuel savings because the transmissions operate more efficiently with less drag.

AMSOIL Synthetic ATV/UTV Motor Oils and Drive Fluids: We touched on the engine oils, but AMSOIL also has ATV/UTV Transmission & Differential Fluid. Many side-by-sides (Polaris, Can-Am) have separate gearbox or front diff fluids. AMSOIL’s Synthetic ATV/UTV Transmission & Differential Fluid is formulated to:

Handle Shock Loads and Wet Clutches (if present): It provides EP protection for spur and helical gears in UTV transmissions, and also works with any clutch packs in those drivetrains (e.g. some polaris have Hilliard clutches). It resists shear and won’t thin out when those vehicles are crawling or towing. This fluid covers Polaris Demand Drive and Angle Drive fluid requirements and can replace them, offering improved film strength and all-temperature performance.
Protects Against Mud/Water Contamination: Recognizing off-road use, it has strong corrosion inhibitors to protect gears even if some moisture intrudes. It also tends to hold up viscosity even if a bit of water gets in (some fluids can emulsify and lose performance). Of course, you should change if water contamination, but AMSOIL fluid gives a bit more safety margin.
One Fluid for Many: It’s multi-compatible – for example, Polaris front diff uses Demand Drive fluid and rear trans uses AGL fluid; AMSOIL Transmission & Diff Fluid is suggested for both, simplifying inventory.

Coolant and Fuel Additives we’ll discuss next, but it’s worth noting AMSOIL also has Small Engine 4-stroke Oil (10W-30/SAE30 Synthetic Small Engine Oil) tailored to air-cooled engines like generators, mowers, etc., with extra zinc and better heat resistance than automotive oils (since small engines often shear oils and run hotter). Those oils dramatically reduce oil consumption and carbon in small engines, and last longer (allowing safely longer intervals, which is handy for equipment that might otherwise need very frequent changes).

In summary, AMSOIL takes the same approach to these specialty fluids as with engine oils: analyze the failure modes (e.g. hydrostat wear, ATV gearbox shear) and formulate a lubricant that solves those issues and extends service life. Whether it’s a commercial mower hydrostat, a side-by-side’s front differential, or a farm tractor’s hydraulic system, AMSOIL likely has a synthetic fluid that offers stronger protection, cooler operation, and longer service than the conventional oil or OEM-branded fluid you might be using.

Fuel Additives and Cleaners: Maximizing Efficiency and Longevity (P.i.®, Quickshot®, Diesel All-In-One)

While our focus is lubricants, AMSOIL also applies its chemical engineering prowess to fuel additives that keep your fuel system and engine internals clean and efficient. Clean fuel systems and combustion chambers translate to more power, better fuel economy, and lower emissions. Let’s highlight a few:

AMSOIL P.i.® Performance Improver (Gasoline Additive): P.i. is a concentrated detergent-based fuel system cleaner for gasoline engines. It’s designed to be used every 4,000 miles (or as needed) by adding a bottle to a tank of gas. P.i. aggressively cleans deposits throughout the fuel system:

Restores Injector Flow and Fuel Economy: With powerful polyetheramine (PEA) detergents, P.i. can clean dirty fuel injectors back to a 100% flow rate in one tank[167][168]. In tests on GDI injectors, it completely removed tip deposits that were restricting flow[168][169]. By restoring proper spray pattern and fuel delivery, engines regain lost fuel economy and smoothness. AMSOIL’s data shows using P.i. can improve fuel mileage (especially if injectors were partially clogged) and restore up to 14% horsepower that was lost to deposits[167][170]. A third-party test on a 5.3L Silverado with 100k+ miles saw a remarkable 14% HP gain after one P.i. treatment[167][171] – illustrating how badly deposits can hurt performance and how well P.i. can remove them.
Combustion Chamber Deposit Removal: P.i. not only cleans injectors, but also cleans intake valve deposits (on port-injected engines) and combustion chamber carbon[172][173]. By reducing carbon in the chamber, it helps eliminate pre-ignition knock and “carbon rap” (that pinging or sharp knock that can occur when carbon hotspots ignite fuel prematurely)[172][174]. It also reduces the chance that you’ll need higher-octane fuel to avoid knock, effectively saving you money if your engine was carboned up. P.i. protects against those issues by removing the carbon and preventing its build-up for a time.
Prevents “Sticky Valve Syndrome”: On intake valves, deposits can cause valves to stick or not seat properly. P.i. helps keep valves clean and moving freely[175][176]. This ensures consistent compression and valve sealing.
Reduces Emissions and Need for Premium Fuel: By cleaning the entire system, P.i. can improve combustion efficiency, which typically lowers HC and CO emissions (more fuel is burned completely). AMSOIL notes that it reduces the need for costly higher-octane fuel in engines that had developed carbon-induced compression increase or knock[177][178] – basically, after cleaning, many engines can run on regular gas again without pinging because the effective compression (and hot spots) are reduced. This can be a significant cost saving.
Capless-Compatible Bottle & Easy Use: The bottle is designed to work with capless fuel fillers (many modern cars have no gas cap)[179][180]. One bottle treats up to 20 gallons typically (30 gallons maximum)[181], making it convenient (just dump and fill). The idea is minimal hassle for maximum benefit.

In practice, users of P.i. often report noticeably smoother idle, improved throttle response, and a bump in MPG after use – especially if the vehicle was never treated before and had high miles. It’s arguably one of the most potent PEA cleaners on the market (PEA is the same type of ingredient found in the famed Chevron Techron®, but P.i. has it in high concentration). It’s safe for catalytic converters and O2 sensors, and because you don’t use it continuously (just occasionally), it’s very cost-effective. Considering the engine is one of the most expensive parts of the car, a periodic $10-$15 treatment to keep it at peak is a wise investment.

AMSOIL Quickshot® Gasoline Treatment & Stabilizer: Quickshot is a multi-function additive aimed at small engines, powersports, and any gasoline equipment that may experience ethanol-related issues or intermittent use. It’s formulated to be used more frequently (even every tank) in things like motorcycles, boats, lawn equipment, etc. Key benefits:

Ethanol Protection: Ethanol in gas (E10, E15) can attract water and phase-separate, causing drivability issues and corrosion. Quickshot is designed to keep water dispersed in tiny molecules throughout the fuel so it passes harmlessly through and doesn’t accumulate[182][183]. This prevents the layer of water/ethanol from forming at the bottom of the tank (which is what causes stalling and lean runs). By keeping the fuel homogenous, Quickshot helps avoid lean-burn conditions and engine damage that phase separation could cause[184][185].
Deep Cleans Small Fuel Systems: Quickshot has strong detergents that clean varnish, gum, and insoluble debris from carburetors, fuel injectors, and fuel filters in small engines[186][187]. Small engines often suffer from gum deposits in jets and passages (especially after storage). Quickshot clears those out, restoring proper fuel flow. It also cleans combustion chamber deposits (on piston tops, spark plugs) to reduce pre-ignition and improve throttle response[188][189]. Basically, it can rejuvenate a lawn mower or bike that’s running rough due to fuel varnish.
Prevents Gum and Varnish Formation: It not only cleans existing deposits but also protects against new gum/varnish buildup in fuel tanks and systems[190][182]. This is crucial for equipment that sits – Quickshot has a stabilizing component for short-term storage (up to a few months) to keep fuel fresh. It’s not a long-term stabilizer for a year or more (AMSOIL has a separate Gasoline Stabilizer for that), but for over the off-season it works well. By keeping fuel fresher and free of gum, it ensures easy starts when you take that equipment out of storage.
Improves Engine Performance and Starting: By cleaning the fuel system and combating ethanol, Quickshot usage results in easier starting, smoother idling, and fewer hesitations in small engines[188][189]. Many people note their old motorcycle or outboard that needed choke and struggled now starts more readily after a couple tanks with Quickshot. It also helps prevent “rough running” or misfiring that water-contaminated fuel can cause.

Quickshot is often used in motorcycles (street and dirt), ATVs, side-by-sides, snowmobiles, marine outboards, and any lawn/yard equipment. The treat rate is about 8 oz for 6 gallons (for a cleaning dose)[191], or double capacity (12 gallons) for maintenance dose[191]. Many power sports enthusiasts add a splash each fill-up to ensure optimal performance. In essence, it’s like a fuel system insurance for small engines – particularly valuable given the prevalence of ethanol issues (stale fuel is the #1 cause of small engine problems).

AMSOIL Diesel All-In-One (now marketed as Diesel 4-in-1) Fuel Additive: This is a convenient all-season, multi-function diesel additive that combines what would normally be three separate additives: a detergent (injector cleaner), a lubricity improver, a cetane booster, and a anti-gel cold flow improver. It’s formulated to simplify diesel treatment – one product that you can use year-round for all benefits. Major advantages:

Cleans and Protects Fuel System: Diesel All-In-One contains powerful detergents that clean dirty injectors, combustion chambers, and fuel pumps[192][193]. It restores power and torque by removing deposits that cause poor fuel atomization[192]. It also reduces smoke and emissions by ensuring more complete combustion[193]. Additionally, it fights fuel-system corrosion (important with today’s ULSD and possibly biodiesel blends)[193]. The result is smoother operation and regained fuel economy if your injectors were coked up. It’s akin to running a “premium diesel” through your system.
Lubricity Boost for ULSD: Modern ultra-low sulfur diesel fuel can lack lubricity, which is hard on fuel pumps and injectors (especially older rotary pumps or CP4 high-pressure pumps). Diesel All-In-One provides significant lubricity improvement – AMSOIL testing shows it dramatically improved the wear scar results on ASTM D6079 HFRR tests for various U.S. diesel samples[194][195]. It delivers improved wear protection for fuel system components, which can extend their life and prevent costly failures (like the dreaded CP4 pump failure in some trucks). This lubricity addition is crucial if you use “dry” fuels or if you want extra protection running biodiesel blends.
Anti-Gel Cold Performance: Diesel All-In-One lowers the Cold Filter Plugging Point (CFPP) by up to 40°F (22°C)[196]. That is a huge benefit in winter – it means your diesel fuel won’t gel or clog filters down to much lower temperatures than it otherwise would. It prevents wax crystals from clogging fuel lines/filters and also contains a de-icer to handle any water that might freeze[196][197]. With Diesel All-In-One, many users can avoid separate anti-gel additives or blending with kerosene down to pretty extreme temps (actual protection depends on base fuel properties, but that 40°F improvement is substantial). It improves startability and engine reliability in cold weather, as noted[196][198].
Cetane Increase: It raises the cetane number up to 4 points[199][200]. Higher cetane means easier ignition, especially in cold conditions, and often quieter operation. It can yield up to 8% improved fuel economy due to more complete combustion[199][201], and you’ll likely notice smoother idle and less white smoke on cold starts. More cetane also typically means a bit more power and throttle response.

Overall, Diesel All-In-One is about convenience and comprehensive fuel quality enhancement: It keeps injectors at peak flow, adds lubricity (like adding the properties of old high-sulfur diesel back in), prevents winter gelling, and makes your fuel ignite easier. For a diesel owner, it means less likelihood of injector coking (which can cause power loss or regeneration issues in DPFs), protection for expensive fuel pumps/injectors, no worrying about cold filter plugging when the polar vortex hits, and possibly picking up a mile or two per gallon in efficiency[202][201]. The treat rate is typically one bottle (about 16 oz) per 40 gallons, making it economical per tank, especially weighed against the benefits in maintenance and performance.

Results of Using AMSOIL Fuel Additives: Engines remain closer to “factory clean” inside – which means they run as intended. You get back lost power or MPG, reduce rough running or stalling issues, and protect components from wear or corrosion. These additives are the finishing touch to a comprehensive maintenance regimen. For example, using AMSOIL Signature Series oil addresses lubrication, and adding P.i. every few thousand miles addresses fuel system cleanliness – the combination keeps an engine running like new much longer.

From a fleet perspective, using P.i. or Diesel All-In-One can reduce downtime (less injector replacement, fewer regen issues on diesels due to cleaner burn) and improve the bottom line via better fuel economy. For personal vehicles, it restores driving enjoyment (snappy throttle, smooth idle) and ensures you’re getting all the performance you paid for.

In modern engines like GDI (Gasoline Direct Injection) that are prone to deposits, P.i. can help clean the injectors, though note GDI also suffers intake valve deposits which need other measures since fuel doesn’t hit the valves – but keeping injectors clean is critical there, too, to avoid lean conditions. For small engines, Quickshot is almost a necessity if you use pump gas with ethanol – it prevents so many common carb issues.

One more note: AMSOIL also has Diesel Injector Cleaner and Diesel Cold Flow as separate products for those who want targeted treatment (e.g. in summer you might just use Injector Clean + Cetane Boost for maximum cleaning, and in winter add Cold Flow). But Diesel All-In-One simplifies it by combining those into one bottle for year-round use. It’s very highly regarded; in fact, independent tests (like Spicer lubricity test) have shown AMSOIL Diesel additives to dramatically improve lubricity of ULSD, ranking at the top among many competitors.

Coolants and Cooling System Protection: Heavy-Duty Antifreeze, Passenger Car Antifreeze, and Coolant Boost

AMSOIL’s approach to coolants mirrors its approach to lubricants: use the best technology available (Organic Acid Technology in this case) to provide long-lasting, superior protection. Plus, they have a unique coolant additive to boost cooling performance. Here’s how AMSOIL addresses engine cooling:

AMSOIL Heavy-Duty Antifreeze & Coolant (Prediluted 50/50): This is an extended-life coolant using a Hybrid Organic Acid Technology (HOAT) additive system. It’s formulated for heavy-duty diesel engines (with wet liners) as well as any automotive application that can use a nitrite-free HOAT. It’s essentially a very advanced coolant that:

No SCAs or Extenders Required: It is fully formulated – no need for supplemental coolant additives (SCAs)[203]. Traditional heavy-duty coolants needed nitrite SCAs to combat cylinder liner cavitation and needed periodic extender additions. AMSOIL HD Coolant has all the necessary additives (organic acids and some nitrite for a HOAT balance) to prevent liner pitting on its own, from the get-go[204][205]. It’s nitrite-, phosphate-, silicate-, borate- and amine-free in its formula[206] (meaning it uses organic acids and perhaps some molybdate as the HOAT, which is easier on water pump seals and leaves no abrasive silicate).
Ultra-Long Service Life: It provides protection up to 1,000,000 miles or 8 years (or 20,000 hours) in heavy-duty/off-road use[203][205]. That’s with proper top-off and if no contamination – in practice it means one coolant fill could last the life of the truck’s engine practically, with just monitoring. Even in passenger cars, it’s good for 150,000 miles or 5 years (because cars typically have shorter spec). This is truly “fill-for-life” for many users – no more biannual coolant flushes.
Superior Heat Transfer: It uses ethylene glycol base (for best heat transfer) plus additives that ensure excellent heat exchange and no insulating deposits[204][207]. It virtually eliminates scaling (thanks to no phosphate or silicate)[205][208]. This keeps heat-transfer surfaces (inside radiator tubes, cylinder head jackets) clean, so cooling efficiency remains high. That means the engine is less likely to overheat under heavy load because the coolant isn’t fouled by scale.
Corrosion and Cavitation Protection: HOAT coolants create a protective film on metals. AMSOIL’s formula provides excellent corrosion protection for all common cooling system metals – aluminum, cast iron, steel, brass, copper, solder – as evidenced by essentially zero corrosion in ASTM tests[209][210]. In an ASTM D2570 test, cast iron and copper coupons showed virtually no corrosion when protected by AMSOIL coolant[210]. Similarly, it prevents liner cavitation – ASTM D7583 results showed virtually no cavitation erosion on wet liner samples with AMSOIL[67]. In short, it stops the two big diesel engine killers: corrosion and liner pitting.
Compatibility: It’s compatible with all other coolant colors and chemistries[206]. That means it can be used to top-off other systems or mixed if necessary (though for best performance, a full flush is recommended to gain AMSOIL’s full benefits). It also means if you switch to AMSOIL, any residual old coolant won’t cause issues – AMSOIL coolant’s additives can handle mixing without precipitating or gelling. It also is safe on all hoses, plastics, gaskets used in cooling systems.

For fleet owners or diesel RV owners, etc., AMSOIL HD Coolant is a game-changer: fewer coolant changes (saves time and disposal costs), no additive hassle, better cooling, and peace of mind that liners won’t pit. Some classic car owners also like it because its HOAT formula (specifically a low-silicate, phosphate-free mix) is gentler on old soldered radiators and copper, and it prevents corrosion during storage.

AMSOIL Passenger Car & Light Truck Antifreeze & Coolant: This is a separate formula (also 50/50 premix) aimed at cars and light trucks. It uses an advanced Poly-Organic Acid Technology (OAT) formula (likely similar to Dex-Cool but improved). Features:

Wide Vehicle Compatibility: It’s a unique poly-OAT that can be used in a wide variety of vehicles – basically it’s designed as a universal automotive coolant[211]. It exceeds OEM requirements and is free of phosphate, nitrite, silicate, borate, amines (so it won’t cause issues in European or Asian cars either)[212]. The “poly” means it likely has multiple organic acids to cover different metal protections (similar to BASF’s Glysantin formulas).
Long Life: Protects for 150,000 miles or 5 years in normal passenger car use[211][213]. That’s in line with or longer than most OEM “long-life” coolants (many say 5yr/150k for first fill and less for subsequent; AMSOIL effectively gives you a first-fill quality extended life even when used as a service fill).
Superior Protection: Like the HD coolant, the passenger car coolant provides superior heat transfer and corrosion protection[214][213]. It practically eliminates scaling (no phosphate/silicate means no scale deposits)[213][215]. It’s excellent at preventing corrosion on all metals – the ASTM D2570 test shows virtually no corrosion on test coupons with AMSOIL coolant[216]. And since most modern cars have lots of aluminum, the OAT formula is ideal for protecting aluminum heads and radiators long-term (no silicates which can cause abrasive wear on water pump seals, etc.). It’s also safe for mixed metal systems (older cars with copper/brass radiators, etc.).
Maximizes Cooling Efficiency: With no scale and no foam issues, plus being pre-mixed with high-purity water, it ensures optimal cooling performance – no insulating deposits, so engines run at intended temps and radiators operate at full efficiency[217]. It also has anti-foam to prevent foam (which can reduce cooling and promote corrosion).

In practice, using AMSOIL Passenger Car coolant when you flush can extend the interval such that you might not need to touch it again for many years. For example, if you flushed your coolant at 100k and put this, you could realistically go to 250k on the same fill (as long as it’s checked and topped if needed). Also, because it’s compatible with “all colors”, if you’re mixing types or unsure of what’s in the car, AMSOIL coolant can simplify things – you can flush or partly flush and fill with AMSOIL and know you’ve got a premium long-life coolant in there.

Given the emphasis AMSOIL puts on preventing corrosion and cavitation, these coolants are particularly appealing for those who want to “fill it and forget it” with confidence – for instance, an antique car that isn’t driven a lot but needs the best corrosion protection while it sits, or a daily driver that you want to minimize maintenance on.

AMSOIL DOMINATOR® Coolant Boost: This is a coolant additive that improves heat transfer and reduces engine temperatures. It’s popular in racing or towing where extra cooling margin is needed, and also helps in cold weather warm-up. How it works and benefits:

Three-Tier Surfactant Technology: Coolant Boost uses three different surfactants, each active at different temperature ranges[218][219]. Surfactants reduce the surface tension of water/coolant, allowing better contact with metal surfaces. By having multiple types, AMSOIL ensures that from lower operating temps to very high temps, there is always a surfactant working to maximize liquid-to-metal contact[218][220]. This increased contact means heat transfers more efficiently from hot metal (like cylinder head or block) into the coolant.
Reduced Engine Temps – Up to 25°F drop: With improved heat transfer, engines run cooler under the same conditions. AMSOIL claims up to 25°F reduction in coolant temperature[221][222]. This is significant, especially for race engines which might otherwise be borderline overheating. It can be the difference between 230°F and 205°F coolant temp under load, which in turn could allow more aggressive tuning or just provide a safety buffer.
Faster Warm-Up – 54% faster to operating temp: Coolant Boost also helps engines warm up quicker in cold weather[221][223]. By improving heat transfer from combustion into the coolant initially, it brings the coolant (and thus the engine metal and oil, indirectly) to temp faster. AMSOIL measured an average 54% faster warm-up time to 180°F coolant temp in cold ambient tests[223]. For daily driving, this means you get heat in the cabin sooner (defroster and heater start working faster)[224], and engine reaches its efficient operating range quicker, possibly improving fuel economy and reducing wear (most wear occurs when engine is cold).
Corrosion Protection in Water: Many racers run straight water with additive (no glycol) for better cooling and because some tracks prohibit glycol. Coolant Boost contains corrosion inhibitors, so it helps prevent rust and corrosion even when running straight water[225][226]. In industry tests, it showed minimal corrosion on common metals (copper, solder, brass, steel, cast iron, aluminum)[225][226]. It basically supplements your coolant’s inhibitors. So even if you use it with antifreeze, it’s adding to the corrosion protection package.
Radiator Safe & Universal: It’s safe for all radiators and pumps (no ingredients that harm water pump seals). It’s compatible whether you run 100% water, or any glycol mix. Many people use it in summer for extra cooling and leave it out in winter (or use year-round, it won’t hurt). It’s concentrated – typically one bottle treats a typical cooling system (perhaps 1.5 bottles for larger systems).

In effect, Coolant Boost is a “secret weapon” for cooling systems. For a race car or towing truck pushing its cooling capacity, it can provide that extra margin to prevent overheating. For a street car, using it might allow you to run a higher percentage of water (which cools better than glycol) without worrying about corrosion, thus getting better cooling performance too. And the quick warm-up is a nice perk for street use in cold climates.

People who use Coolant Boost often report a noticeable drop in coolant needle position under heavy load, and some dyno tuners use it to help control temps during tuning runs. It’s an inexpensive add-on for what it does (improve efficiency of the cooling system).

Conclusion on Coolants: AMSOIL’s coolants ensure complete, long-term protection of cooling systems – reducing maintenance frequency (due to extended life), preventing mechanical failures like head gasket issues due to overheating or liner cavitation, and even contributing to better engine performance by optimal temperature control (with Coolant Boost). They’re part of a holistic approach to vehicle longevity. Using AMSOIL coolant and coolant boost together can give you a rock-solid cooling system: one that warms up fast, runs cool under load, and doesn’t degrade or corrode over years.

Filtration and Oil Analysis: Extending Protection Through Ea® Filters and Monitoring Programs

Even the best oil benefits from proper filtration. AMSOIL not only focuses on fluids but also on filters that match their extended-drain philosophy and performance standards. Additionally, AMSOIL offers oil analysis services to help users safely maximize drain intervals and monitor engine health.

AMSOIL Ea® (Absolute Efficiency) Oil Filters: These are AMSOIL’s top-of-the-line full-synthetic media oil filters, designed for extended use while providing superior filtration. Key attributes:

Exceptional Filtering Efficiency: Ea Oil Filters provide 99% efficiency at 20 microns (per ISO 4548-12 test)[227][228]. In fact, AMSOIL often cites 98.7% at 20 microns and even high efficiency at smaller sizes like 15 microns. This means they trap an extremely high percentage of fine particles (the ones that cause engine wear) that typical OEM or economy filters might let through. Many standard filters are only ~95% at 20 microns; AMSOIL Ea filters are virtually absolute at that size, hence the name.
Nanofiber Synthetic Media: The filter media is a nanofiber technology (developed with Donaldson) that has very uniform pore size and high capacity. Synthetic fibers are smaller in diameter than cellulose, creating more pores for oil to flow but also finer filtration. This allows Ea filters to stop tiny contaminants without restricting flow. The result is both high efficiency and high flow.
Long-Life Capacity: The synthetic media holds much more contaminants than traditional filters (which often use cellulose or cellulose/glass blend). AMSOIL Ea filters are typically rated for 15,000 miles or 1 year in normal service, with some extended to 25,000 miles for certain applications (when paired with AMSOIL Signature Series oil). They have greater capacity for small, wear-causing particles than ordinary filters[227]. So they won’t clog even during extended drains. Higher capacity means the filter can accumulate a lot of soot and debris (especially important in diesels or DI engines that may produce more soot) without bypassing or starving the engine of oil.
Sturdy Construction & Burst Strength: Ea filters have heavy-duty canisters and excellent burst pressure ratings, along with quality nitrile or silicone anti-drainback and bypass valves where applicable. They’re built to withstand long service and pressure spikes (e.g. cold starts at -20°F with thick oil). So reliability is not compromised during a long interval.
Bypass and Auxiliary Filters: AMSOIL also offers Ea Bypass filters (which filter oil continuously at ~2 microns, 98.7% efficient, for those who install bypass systems) – these can remove extremely fine soot and extend oil life dramatically by keeping oil ultra-clean. Many AMSOIL customers with big diesels use bypass systems to safely run very long oil intervals (with periodic top-offs). The Ea Bypass filters are among the best, catching 98.7% at 2 microns which is incredible (most wear is from <10µ particles, so that basically eliminates wear particles).

In practice, switching to an AMSOIL Ea filter means your oil stays cleaner (fewer particles circulating). This reduces engine wear over time – it’s been said a good filter is like giving your engine “cleaner blood” to run on. For example, an engine with an Ea filter might show less iron/copper/etc. in UOA because fewer abrasives are in the oil causing wear. Also, the extended capacity means you don’t have to change the filter mid-way if you’re doing a long drain – you can do one filter per oil change, even at 15k+ miles, and trust it has plenty capacity left.

The efficiency especially matters in modern engines with tight tolerances (like GDI engines with timing cam phasers that can get gummed by particles, or turbo bearings that need clean oil). AMSOIL filters ensure minimal particles get through to cause deposits or wear. On older engines, if you have some blow-by or sludge, the high capacity helps trap that sludge and not clog quickly.

Oil Analysis Program (OIL ANALYZERS INC.): AMSOIL has an oil analysis division that provides test kits for customers to send oil samples to a lab. The oil analysis can measure viscosity, TBN, oxidation, fuel dilution, coolant presence, and wear metals. The benefits and how it complements AMSOIL usage:

Optimizing Drain Intervals: By periodically analyzing your oil, you can see how well the oil is holding up (TBN remaining, oxidation level) and how much additive is left. This data allows you to confidently extend drains only as far as the oil can handle. For instance, maybe your usage is mostly highway and you find at 15,000 miles the Signature Series oil still has TBN of 4 and low wear metals – you could likely go 20,000 safely, saving money. Conversely, if you tow heavy and analysis at 10k shows the oil is stressed (TBN low, viscosity thickening), you know to change a bit sooner. It takes the guesswork out, and since AMSOIL oils are built for it, they often show excellent results even at long intervals.
Early Problem Detection: Oil analysis can flag issues like coolant leaks (presence of potassium/sodium or glycol), excessive fuel dilution, or unusual spikes in wear metals. Catching these early can save your engine. For example, if analysis finds 1% coolant, you might address a minor leak before it turns into a blown head gasket. Or high fuel could indicate an injector issue. It’s essentially a blood test for your engine.
Warranty/Peace of Mind: For those running extended intervals, having analysis records can protect you in warranty situations – it documents that the oil was still serviceable and no abnormal wear was occurring. But more so, it gives you peace of mind that you’re not harming anything by going longer. Many AMSOIL users will do a sample at mid-point of a long drain just to check everything, then keep going if all is well.
Long-Term Engine Health Trends: Doing yearly or biannual oil analyses builds a trendline of wear metals. AMSOIL customers (especially fleets) do this to track engine health. If wear metals remain low and stable over time, that engine is in great shape. If something trends upward, they can investigate before a failure. It essentially validates that AMSOIL’s protection is working. And indeed, many analyses of AMSOIL users show extremely low wear metal counts – evidence of how well the oil/filters protect.

In combination, using AMSOIL oil + AMSOIL Ea filter + occasional oil analysis is a strategy to maximize engine life and minimize maintenance costs. Engines have been documented going hundreds of thousands of miles with like-new internals following this strategy. For instance, there are cases of pickup trucks or taxis using AMSOIL for 250k+ miles; upon tear down, engine components were still within spec and clean because the oil was always kept clean and not run past its limits[233][4].

Even if you’re not doing extended drains, the Ea filter’s superior filtration means you’re eliminating more abrasive wear. That, combined with AMSOIL’s superior lubrication, means wear rates are significantly reduced vs. standard oil & filter. For high-performance or classic cars, that’s important (keep that matching-numbers engine healthy!). For daily drivers, it means potentially doubling or tripling the engine’s service life before any major issues.

One more note on AMSOIL filters: They also offer Ea Air Filters (for some applications) using nanofiber media, which filter better and hold more dirt than typical cotton or foam or paper filters. A cleaner intake air means less dirt enters the engine (which then less dirt gets to oil, etc.). And fuel filters in the AMSOIL line (for diesels) that also have high efficiency. It’s an ecosystem of high-quality filters to keep everything clean.

In summary, AMSOIL's approach to filtration and analysis ensures that the protective fluids can do their job to the fullest:

· The fluids (oils, etc.) bring the high performance and longevity.

· The filters maintain fluid cleanliness and integrity over those long service intervals.

· The analysis confirms everything is working as intended and helps fine-tune the program.

This trifecta is what allows AMSOIL to confidently claim extended drains and superior protection. It’s a system. And the user benefits with a vehicle that runs optimally with less maintenance downtime.

Conclusion

Across every category – from engine oils to gear lubes, transmission fluids, greases, fuel additives, and coolants – AMSOIL delivers products that push the boundaries of chemical engineering to offer maximum protection, performance, and extended service life**. The data and test results we’ve explored demonstrate that:

AMSOIL motor oils (Signature Series and others) far exceed industry standards in wear protection[234], cleanliness[9], and longevity[19] – translating to longer-lasting, smoother-running engines.
AMSOIL diesel oils guard critical components under extreme conditions, preventing wear by factors of 4× to 6× better than required[48][61] and keeping engines clean and efficient even over extended drains.
AMSOIL gear oils and transmission fluids solve problems like shear breakdown, thermal runaway, and friction loss, thereby extending equipment life (fewer diff rebuilds, smoother shifting transmissions) and maintaining performance (no clutch glaze or gear whine).
AMSOIL greases stay in place and lubricate when others fail – meaning pins, bearings, and joints can operate longer without failure or frequent re-greasing[79][122].
AMSOIL 2-stroke and small-engine oils keep those engines practically carbon-free[141] and protected on lean mixes, solving issues like fouled plugs, stuck rings, and smoky exhaust, while their 4-stroke powersport oils handle high RPM and shared engine/gearbox environments with ease[235][236].
AMSOIL fuel additives and coolant products ensure that the supporting systems (fuel system & cooling system) do not become the weak link – your fuel injectors stay clean for optimal combustion[170], and your engine temps are controlled even in extreme conditions[222][224].
AMSOIL filters capture nearly all damaging particles while flowing enough for extended use[227][228], and oil analysis provides the feedback loop to safely harness the full potential of these advanced lubricants.

In essence, AMSOIL has built a comprehensive lubrication and maintenance solution. It’s not just about an oil; it’s about every fluid and filter contributing to the overall reliability and efficiency of your machinery – whether that’s a high-mileage commuter car, a fleet of semis, a racing vehicle, a fishing boat, or a lawn mower.

For those “serious gearheads, fleet owners, installers, and power users” who demand proof and performance rather than marketing hype, AMSOIL consistently provides the hard data: independent tests, ASTM sequence results, and real-world case studies all backing up the claims[3][19][192]. This technical deep-dive hopefully conveyed just how and why AMSOIL products achieve their reputation. They formulate lubricants with a singular devotion to being the best – often “over-engineered” with built-in safety margins and performance reserves[25]. And they’ve been doing it since the 1970s, continuously innovating as engine technologies evolve (from flat-tappets to today’s turbo GDI and beyond).

The practical benefits to the end-user are tangible: extended equipment life, less downtime, optimal performance (power & efficiency), and possibly even lower total cost of ownership (fewer oil changes and failures). An enthusiast might care that their engine is protected against wear during occasional track days, while a business owner might value that their delivery trucks can safely double oil drain intervals and avoid unscheduled maintenance – AMSOIL speaks to both by delivering performance through science.

In a competitive lubricant market filled with big claims, AMSOIL stands out by backing theirs with technical evidence and by focusing solely on producing the highest-quality lubricants rather than also producing fuel or other business distractions. Their niche specialization has earned them a trust in critical applications (even NASA rovers have used AMSOIL greases in tests for space, as anecdote goes). Whether or not that’s apocryphal, it underlines the confidence advanced users have in the brand.

So, why is AMSOIL the best lubricant brand? Because it consistently demonstrates technical superiority in every category – better base stocks, stronger additive packages, rigorous testing, and an unwavering commitment to maximum performance. For those who demand the best for their engines and equipment, AMSOIL delivers a level of protection and capability that truly “blows the doors off” the highest industry standards[39], setting new benchmarks for others to chase.

References (from amsoil.com and AMSOIL product data):

· Engine Oil Performance: Wear protection and cleanliness claims[3][19][10]

· Diesel Oil Testing: DD13 Scuffing Test, turbo, consumption[48][57]

· Gear Lube Benefits: High-load protection, thermal runaway prevention[237][70]

· ATF durability: Double service interval, 180k mile test results[90][91]

· Grease Specs: Off-road adhesion and moly content[79][120], Multi-purpose shear stable and EP performance[129][238]

· 2-Stroke Oil Performance: SABER deposit free at 100:1[141], INTERCEPTOR prevention of ring/valve sticking[147][148]

· Small Engine Fluids: Zero-Turn Hydrostatic benefits[162][239], ATV/UTV oil severe service protection[159][160]

· Fuel Additives: P.i. restoring power/injector flow[167][170], Quickshot ethanol protection and cleaning[184][187], Diesel All-In-One improvements (lubricity, cold flow, cetane)[192][196]

· Coolants: Heavy-Duty coolant longevity & cavitation prevention[205][67], Passenger Car coolant long life & corrosion free performance[213][216]

· Coolant Boost: Temp reduction and faster warm-up proof[221][223]

· Filters: Ea Oil Filter efficiency and capacity[227] (98.7% @ 20μ), Bypass Filter efficiency (98.7% @ 2μ).

Each of these sourced points reinforces how AMSOIL products excel in specific technical criteria, collectively painting the picture of a brand that truly earns the title of “best lubricant” through innovation and quality. When you choose AMSOIL – be it for your engine, transmission, differential, or even fuel system – you’re effectively giving your machinery the advantage of longer-lasting, better-performing lubrication that has been proven in both laboratories and the real world.

And that is why AMSOIL stands at the forefront of lubricant technology – delivering Proven, Edge-to-edge protection for all your lubrication needs.

[3][19]

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https://www.amsoil.com/p/amsoil-signature-series-5w-30-100-synthetic-motor-oil-asl/?srsltid=AfmBOoqKHakoyu8CMyAZSdsfphRVH4K1WWehhIr0pNb0PvFD1nt0fXcz

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https://www.amsoil.com/p/amsoil-interceptor-100-synthetic-2-stroke-oil-ait/?srsltid=AfmBOoqFw4rCfzAf-M8CdrczUwvjOb2Ux-LCI7Q5zo1rXU3ECNUGhV1j

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[60] AMSOIL Performance Test

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https://www.amsoil.com/p/amsoil-heavy-duty-antifreeze-coolant-anthd/?srsltid=AfmBOooyPslMD__uxSZyhpcihsZ4fz93CHO-t1XbURfAlC6OT6e8o8Ag

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https://www.amsoil.com/p/amsoil-severe-gear-75w-90-100-synthetic-gear-lube-svg/?srsltid=AfmBOoqOTA27YlZQcR7QwKD2wJI7Z-OMje0TMs200yI2ALKxEP7oSWjv

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https://www.amsoil.com/p/amsoil-nlgi-2-100-synthetic-polymeric-off-road-grease-gpor2/?srsltid=AfmBOoruTqBVnEcHroODWYpK8IZxWX1OdhE4J6MovNmuCG1d995PzzUd

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https://www.amsoil.com/p/amsoil-75w-90-long-life-100-synthetic-gear-lube-fgr/?srsltid=AfmBOor6r998BOocUaprusXc4Zniw2kUzp8DNskgbf1XeS5ibIEDJHxr

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https://www.amsoil.com/p/amsoil-signature-series-multi-vehicle-100-synthetic-automatic-transmission-fluid-atf/?srsltid=AfmBOoqFQt0Wek5gA-ePSHcg9rTZnMNo51flSB7DlzhfwqKDtvvAVxx5

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https://www.amsoil.com/p/amsoil-torque-drive-100-synthetic-automatic-transmission-fluid-atd/?srsltid=AfmBOoq_ZTtGqa7RR-Jf3FDthFcoU1h3f50aRN45YetWLySpstB3jQiO

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https://www.amsoil.com/p/amsoil-100-synthetic-cvt-fluid-cvt/?srsltid=AfmBOooSI9c_TB4i_aLBhw7JLiksOaSja0C9RUSXXQCyKOy0_Zpz7mtP

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https://www.amsoil.com/p/amsoil-100-synthetic-dct-fluid-dct/?srsltid=AfmBOoppRZlV86t_CG2bFQTgiZxOH51uXkyUx2YlgOC_2oO-zyRjO-nJ

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https://www.amsoil.com/p/amsoil-100-synthetic-multi-purpose-grease-glc/?srsltid=AfmBOopliuecv9kXZ3rSC9ceKIx_BKx9VrkAL2ihGJG5Jd5nwoKMPz9W

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https://www.amsoil.com/p/amsoil-dominator-100-synthetic-racing-grease-grg/?srsltid=AfmBOooA-95Sj7o5BPEa-0jUVbvenMhVMLSo8wH7B3c_TL-bCX2OXfDO

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https://www.amsoil.com/p/amsoil-saber-professional-100-synthetic-2-stroke-oil-atp/?srsltid=AfmBOopVfDLKJvvXUWHxsNWrKlvLCMkYzPb0FuuFMi37pNDryvp4Wjrg

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[158] Customer Reviews: AMSOIL HP Marine® 100% Synthetic 2-Stroke ...

https://www.amsoil.com/reviews/amsoil-hp-marine-100-synthetic-2-stroke-oil-hpm/?page=2&srsltid=AfmBOorp6MsS8d-Nh1HeevYORS67osf4BiJwm6qvpuXsXbQTiXqhUIR_

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https://www.amsoil.com/p/amsoil-10w-40-100-synthetic-atv-utv-motor-oil-auv40/?srsltid=AfmBOop2HGVjjNnmOKT2BfaV2Rctr4dlJYlXYuOZuZFoINFUajNxsjGM

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https://www.amsoil.com/p/amsoil-20w-50-100-synthetic-hydrostatic-transmission-fluid-ahf/?srsltid=AfmBOooEdQgF4yhZm6kPsp-OsFdwnHU_zHNtMtAyjZhJJIj6MjXRhdS0

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https://www.amsoil.com/p/amsoil-dominator-coolant-boost-rdcb/?srsltid=AfmBOorNVgS979A8LZWHFNWp2JLXAKMB7LE27J5rWcyCGrUb2RFUwx1n

[227] Ea Oil Filters - AMSOIL

https://www.amsoil.com/p/amsoil-oil-filter-eaoilfilt/?srsltid=AfmBOoo-FN70KGVF8YoNihL-J1Yo8UR5FSCNo_npkhnwkJBszYWIp4Ih

[228] AMSOIL Heavy-Duty Oil Filter

https://www.amsoil.com/p/amsoil-heavy-duty-oil-filters-eahd/