AMSOIL Signature Series Oil, Transmission Fluid & More

Learn more about and purchase AMSOIL Signature Series synthetic oil products, transmission fluids, and merchandise.
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AMSOIL Signture Series Motor Oils

Helpful Tips from Dave Mann

While AMSOIL offers many different types of gasoline engine oil, the most popular motor oils are the Signature Series, High Mileage, Extended Life (XL), and the OE (Original Equipment) Synthetic Motor Oils.

I prefer to run the Signature Series oils in my gas engines because that line is the best of the best and saves me time and money in the long run.

Signature Series vs. High-Mileage vs. XL vs. OE

Signature Series provides up to 25,000 miles of protection (or one year) when combined with the AMSOIL EAO Filter, Extend-Life (XL) offers 20,000 miles of protection between changes, High-Mileage can run 12,000 in engines over 75k miles, and OE (Original Equipment) recommends following the manufacturers specifications.

AMSOIL Signature Series Gas Engine Oils

Is AMSOIL Signature Series Worth It?

AMSOIL Signature Series oils are premium synthetic oil products. While you might pay a bit more up front, I have saved a lot of money in the long run since my vehicles are more fuel efficient and they have had much less down time for maintenance and experienced extended drain intervals between oil changes.

AMSOIL Signature Series Sequence IVA Engine Test for API SN PLUS

The Sequence IVA Engine Test, which must be passed to meet the API SN PLUS specification, simulates extended periods of stop-and-go driving. For 100 hours, the test engine cycles between 50 minutes of idling and 10 minutes of elevated rpm — conditions that encourage engine wear. The camshaft is then measured for wear in 84 locations and an average score is determined.

We used Signature Series 0W-20, the lightest viscosity in the line, to further increase the severity of the test. AMSOIL Signature Series Synthetic Motor Oil provided 75% more engine protection against horsepower loss and wear (based on independent testing of AMSOIL Signature Series 0W-20 using the ASTM D6891 standard test) than required by the industry standard, extending the life of vital components like pistons and cams.

After rigorous third-party testing, the cam lobes show little-to-no wear.
Sequence IVA Engine Test Results Using AMSOIL Signature Series 0W-20

Signature Series Protects Pistons from Low Speed Pre-Ignition

We armed Signature Series with an advanced detergent system that protects against harmful deposits and low speed pre-ignition (LSPI). Most new engines feature gasoline direct injection (GDI), often combined with a turbocharger to boost power and improve fuel economy. These new technologies, when combined with a poorly formulated motor oil, promote LSPI and threaten engine operation. LSPI is the spontaneous ignition of the fuel/air mixture prior to spark-triggered ignition. It occurs in today’s advanced engines and is much more destructive than typical pre-ignition. A properly formulated motor oil is critical for protecting your engine.

Original equipment manufacturers (OEMs) like GM* have addressed the issue by designing tests to determine a motor oil’s ability to prevent LSPI. Signature Series Synthetic Motor Oil achieved 100% protection against LSPI (based on independent testing of AMSOIL Signature Series 5W-30 motor oil) in the engine test required by the GM dexos1 Gen 2 specification - zero occurrences were recorded throughout five consecutive tests.

Example of piston damage due to an LSPI event observed during the testing of a competitor's motor oil. The red arrows indicate sections of the ring land that broke away from the piston.

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