1Based on independent testing of AMSOIL Signature Series 0W-20, in ASTM D6891 as required by the API SN specification.
Signature Series Fights Wear
75% more engine protection against horsepower loss and wear.A
Signature Series Fights Viscosity Breakdown
AMSOIL fights viscosity breakdown better than the competition,O providing superior protection of pistons, cams and bearings.
Signature Series Delivers Powerful Protection
AMSOIL delivers powerful protection. How good is it? An independent lab compared AMSOIL synthetic motor oil head-to-head against a leading competitor in a 100,000-mile test.PAMSOIL provided far superior wear protection and kept bearings looking like new.
Signature Series Protects Against LSPI
AMSOIL Synthetic Motor Oils achieved 100% protection against LSPI.B
BBased on zero LSPI events in five consecutive tests of AMSOIL Signature Series, XL and OE 5W-30 Motor Oil in the LSPI engine test required by the GM dexos1 Gen 2 specification.
Signature Series Resists Viscosity Increase
Signature Series is barely challenged by the industry-standard testing, demonstrating only a 0.1% viscosity increase. Even when the test length is doubled, AMSOIL delivered twice the viscosity control required by the standard.GG
Keeps Engines Clean
Formulated with superior thermal durability that resists breakdown and keeps pistons clean.
Controls heat and minimizes performance-robbing deposits.
Maximizes engine life and performance.
Helps Keep Engines Cleaner
Signature Series is fortified with a heavy treatment of detergent additives, delivering 28 percent more acid-neutralizing power than Mobil 1* and helping engines stay cleaner, longer.LL
LLBased upon independent testing of Mobil 1 Annual Protection Full Synthetic 5W-30 and AMSOIL Signature Series 5W-30 in ASTM D2896. Oils purchased July 2020.
Signature Series Guards Turbos
Protects turbochargers 72% better than requiredC by the GM dexos1* Gen 2 specification.
Signature Series Cleans
Signature Series has 50% more detergentsD to help keep oil passages clean and promote oil circulation. It provides 90% better protection against sludge.DD
DDBased on independent testing of AMSOIL Signature Series 5W-30 in the ASTM D6593 engine test for oil screen plugging as required by the API SN specification.
Signature Series Neutralizes Acids
AMSOIL Signature Series is fortified with a heavy treatment of detergent additive and it delivers 30% more acid neutralizing powerE than Mobil 1,* and 36% more than Royal Purple,* helping engines to stay cleaner, longer.
Signature Series Helps Keep Valves Clean
AMSOIL fights volatilityU 38% better than Mobil 1* and 17% better than Royal Purple,* helping reduce oil consumption and keep valves clean.
Keeps Pistons Cleaner
Even after doubling the length of the industry-standard test, AMSOIL delivered 40% cleaner pistons than required by the standard.FF
Trusted by Professionals
Dedicated engine builders and mechanics put in long hours honing their craft. These architects of powerful, high-performance engines turn to Signature Series to protect their passion.