AMSOIL Gasoline Motor Oil
AMSOIL Signature Series is the top gasoline motor oil in the AMSOIL lineup, built for strong wear protection, clean operation, and dependable performance in demanding service.
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| Product code | Package size | Unit of measure |
|---|---|---|
| AZFQT-EA | Quart | Each |
| AZFQT-CA | Case of 12 Quarts | Case of 12 |
| AZF1G-EA | Gallon Jug | Each |
| AZF55-EA | 55 Gallon Drum | Each |
AMSOIL Signature Series 0W-40 100% Synthetic Motor Oil is a fully synthetic gasoline engine oil engineered for high-output, performance, and severe-service applications that specify an SAE 0W-40 viscosity. The formulation meets API SP, API SN Plus, and API SN, alongside Chrysler, Nissan GT-R, and GM dexos R approvals, and suits high-performance V-engines, late-model Hemi platforms, and sustained-load duty cycles.
Signature Series develops a strong fluid film that keeps metal surfaces separated, reinforced by anti-wear additives that reduce wear in metal-to-metal contact regions. Signature Series provides 75 percent more engine protection against horsepower loss and wear than required by the industry standard, based on independent testing of Signature Series 0W-20 in the ASTM D6891 Sequence IVA Engine Test required by the API SN specification. The 0W-40 grade carries the same additive package into a heavier viscosity tier that holds film strength under higher operating temperatures.
Low-speed pre-ignition (LSPI) is the spontaneous ignition of the fuel and air mixture before the spark fires, a destructive event in turbocharged gasoline direct-injection engines. Signature Series delivered 100 percent protection against LSPI, with zero LSPI occurrences across five consecutive runs of Signature Series, XL, and OE 5W-30 in the LSPI engine test required by the GM dexos1 Gen 2 specification, and the same additive chemistry carries into the 0W-40 grade.
Turbochargers create extreme heat at the bearing, which can break weaker oils down and form deposits in a process called turbo coking. Signature Series passed the GM Turbo Coking Test, a 2,000-cycle heat-soak protocol where an oil must keep the temperature change inside the turbocharger to 13 percent or less. The formula limited the increase to 3.6 percent, protecting the turbocharger 72 percent better than required by the GM dexos1 Gen 2 specification, based on independent testing of Signature Series 5W-30. The 0W-40 grade pairs the same oxidation-resistant chemistry with a higher HTHS viscosity for hot-running turbo engines.
Signature Series carries 50 percent more detergents than AMSOIL OE Motor Oil and delivers 28 percent more acid-neutralizing power than Mobil 1, based on independent testing of Mobil 1 Annual Protection Full Synthetic 5W-30 and Signature Series 5W-30 in ASTM D2896 with oils purchased July 2020. The formulation also provides 90 percent better protection against sludge in the ASTM D6593 oil screen plugging engine test required by the API SN specification, leaving the oil pick-up tube screen virtually free of sludge.
The 0W cold rating supports fast oil movement to bearings, cams, and timing components at startup, with a CCS cranking viscosity of 6062 cP at minus 35 C in ASTM D5293 testing required by SAE J300. At operating temperature, Signature Series resists viscosity increase, posting 0.1 percent in the Sequence IIIH Engine Test (ASTM D8111) required by ILSAC GF-6 and API SP, and 49.6 percent at twice the standard test length, well below the 100 percent industry threshold. The doubled IIIH run produced 40 percent cleaner pistons than the standard requires.
NOACK volatility measures oil lost to evaporation under high engine temperatures, and lower numbers translate into less makeup oil between drains and less catalyst-fouling vapor. Signature Series 0W-40 posts 7.7 percent weight loss in ASTM D5800 and a 3.76 cP HTHS viscosity at 150 C in ASTM D5481, the kind of high-shear film performance and tow-duty platforms require.
Signature Series 0W-40 is built for engines that require any of the following specifications: API SP, API SN Plus, API SN, Chrysler MS-A0921, MS-12633, MS-10725, MS-10850, Nissan GT-R, and GM dexos R. The Chrysler approval set covers a range of late-model Hemi V8 and high-performance gasoline platforms that specify a 0W-40 grade. Confirm the required viscosity and approval in the owner manual before refilling.
AMSOIL Oil Filters are designed for extended drain intervals. With other-brand filters, the interval should not exceed 12,000 miles (19,312 km) or one year unless the vehicle manufacturer recommends longer. Signature Series 0W-40 is compatible with other conventional and synthetic motor oils, but mixing shortens oil life, reduces performance benefits, and disqualifies extended drain coverage. Aftermarket oil additives are not recommended with AMSOIL synthetic motor oils.
| Property | Value |
|---|---|
| Kinematic Viscosity at 100 C, cSt (ASTM D445) | 14.8 |
| Kinematic Viscosity at 40 C, cSt (ASTM D445) | 84.6 |
| Viscosity Index (ASTM D2270) | 184 |
| CCS Viscosity, cP at -35 C (ASTM D5293) | 6062 |
| Flash Point, C (F) (ASTM D92) | 222 (431) |
| Fire Point, C (F) (ASTM D92) | 238 (460) |
| Pour Point, C (F) (ASTM D97) | -50 (-58) |
| NOACK Volatility, percent weight loss (ASTM D5800) | 7.7 |
| High-Temperature High-Shear Viscosity at 150 C, cP (ASTM D5481) | 3.76 |
| Total Base Number (ASTM D2896) | 12.5 |
Signature Series 0W-40 is available as a quart bottle (AZFQT-EA), a case of 12 quarts (AZFQT-CA), a gallon jug (AZF1G-EA), and a 55 gallon drum (AZF55-EA). Using AMSOIL synthetic lubricants does not void a new vehicle or equipment manufacturer warranty, and all AMSOIL lubricants and filters are covered by the AMSOIL Limited Warranty. Cross-reference the right grade with the AMSOIL vehicle lookup, compare viscosities in the gasoline motor oil products, then order AMSOIL Signature Series 0W-40 100% Synthetic Motor Oil.
I’ve been using AMSoil for so long I don’t remember when I started, but suffice to say I believe it’s the best oil on the market and when paired with the preferred customer membership it’s the the best value too.
Would recommend this to a friend.
The engine seems to run better
Would recommend this to a friend.
First time using this in my 2018 Silverado. So far it appears to be excellent. Quiet and smooth engine running. Will be using this oil exclusively from now on.
Would recommend this to a friend.
0W-40 is an SAE J300 viscosity grade. The 0W describes cold-start flow, and the 40 indicates a heavier high-temperature operating viscosity than 30-weight oils. The grade fits high-output gasoline engines, performance V8 and twin-turbo platforms, and applications that pair cold-climate startup with hot, high-load operation. Signature Series 0W-40 should only go into engines where the owner manual lists a 0W-40 viscosity or one of the approvals carried by the formula.
Signature Series 0W-40 meets API SP, API SN Plus, and API SN, along with Chrysler MS-A0921, MS-12633, MS-10725, and MS-10850, Nissan GT-R, and GM dexos R. The owner manual should list one of these requirements before the oil is used.
The Signature Series 0W-40 grade is targeted at the Chrysler, Nissan GT-R, GM dexos R, and API approval set listed above. Drivers searching for a 0W-40 with dedicated European OEM credentials should compare against the AMSOIL European Motor Oil line in the AMSOIL vehicle lookup.
At cold-start temperatures, 0W-40 flows faster than 5W-40 because the 0W winter rating uses a lower cranking viscosity threshold in ASTM D5293. At operating temperature, the two grades land in the same SAE 40 band, so the difference is felt mainly during the first seconds after a cold start.
Signature Series 0W-40 supports drain intervals up to 25,000 miles (40,200 km), 700 hours of operation, or one year, whichever comes first, for normal service in personal vehicles inside the United States and Canada. Severe service is capped at 15,000 miles (24,140 km), 700 hours, or one year. AMSOIL Oil Filters are recommended to take full advantage of the extended interval.
Substituting Signature Series 0W-40 in an engine that calls for a lighter viscosity such as 5W-30 or 0W-20 is not recommended. The 0W-40 grade is built only for engines that require the API and OEM approvals listed above. Confirm the correct grade with the AMSOIL vehicle lookup.
No. Using AMSOIL synthetic lubricants does not void a new vehicle or equipment manufacturer warranty. All AMSOIL lubricants and filters are covered by the AMSOIL Limited Warranty.