The Pinnacle of Performance

The new Signature Series Synthetic Motor Oil formulation builds upon its rock-solid foundation to offer enthusiasts a new level of engine protection. Major upgrades to all the lined on the way now!

Signature Series Synthetic Motor Oil

Improving Signature Series was a challenge, but the results prove the new formulation blows the doors off the latest industry standards. Capitalizing on its firmly established success, our upgraded Signature Series Motor Oil provides enthusiasts with maximum protection and performance. The new formulation will become available in September or when current inventory is depleted.

Formulation Change? Yes

Date Available?  September (rolling change)

New Stock Numbers? No

Price Change? No

  • 75 percent more wear protection1
  • 100 percent protection from LSPI2
  • Trusted by professional engine builders
  • Ideal for turbos & direct injection
  • 50 percent more cleaning power3
    •  Guaranteed protection for up to 25,000 miles or 1 year
    (in normal service)


Maximum Wear Protection

Signature Series Synthetic Motor Oil provides
75 percent more engine protection against horsepower loss and wear1 than required by a leading industry standard, extending the life of vital components like pistons and cams. Its strong fluid film keeps metal surfaces separated while its robust anti-wear additives further reduce wear in metal-to-metal contact regions for maximum engine life.

Protects Pistons from Low-Speed Pre-Ignition

We armed Signature Series with an advanced detergent system to protect vital engine parts like pistons and connecting rods. Most new engines feature gasoline direct-injection (GDI), often combined with a turbocharger to boost power and improve fuel economy. These new technologies pose significant challenges to motor oil, one of which is the advent of low-speed pre-ignition (LSPI). 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. Signature Series provided 100 percent protection against LSPI in the engine test required by the GM dexos1® Gen 2 specification.

Protects Turbochargers

The tremendous heat and stress turbos create can cause some oils to break down and form harmful bearing deposits through a process known as turbo coking. Over time, turbos can suffer reduced performance or fail altogether. AMSOIL Signature Series Synthetic Motor Oil handles heat so well that it protects turbochargers 72 percent better than required by the GM dexos1 Gen 2 specification.4 It enables modern engines to achieve their full potential and service life. Signature Series provides the ultimate protection against extreme heat and the harmful deposits that can plague turbochargers and features the high film strength needed to guard against accelerated wear.

Maximum Cleaning Power to Battle Sludge

AMSOIL Signature Series Synthetic Motor Oil has 50 percent more detergents3 to help keep oil passages clean and promote oil circulation. Its detergent and dispersant additives are so effective, Signature Series provides 90 percent better protection against sludge5 than required by a leading industry standard.

Easier Cold-Starts

Signature Series Synthetic Motor Oil does not contain paraffins (wax) and stays fluid in temperatures as low as -58ºF. Extreme cold causes other motor oil to thicken, starving vital moving parts of lubrication, accelerating wear and even preventing vehicles from starting. Signature Series provides 66 percent better cold-temperature performance than conventional oil for easier starting, better fuel economy, improved oil flow and reduced wear.

Reserve Protection

AMSOIL Signature Series Synthetic Motor Oil provides reserve protection, allowing you to go up to 25,000 miles or one year (in normal service) between oil changes if you choose. Its unique synthetic formulation and long-drain additive system are inherently stable to resist oxidation and neutralize acids over longer periods.

Signature Series is designed to deliver outstanding engine protection, cleanliness and performance over extended drain intervals – guaranteed. It provides peace of mind so you can fit oil changes into your schedule, while also reducing vehicle maintenance and waste oil.

Limiting Oil Consumption

Signature Series has a uniform molecular structure that limits evaporation and keeps it where it’s needed most – protecting your engine. Volatility (burn-off) occurs when oil gets hot, causing lighter molecules to burn off or evaporate. Signature Series falls far below the API limit for volatility, reducing the need for frequent oil top-offs and limiting vehicle emissions.


  1. Based on independent testing in the ASTM D6891 test using 0W-20 as worst-case representation.
  2. Based on independent testing in the LSPI engine test as required for the GM dexos1 Gen 2 specification.
  3. vs. AMSOIL OE Motor Oil
  4. Based on independent testing of AMSOIL Signature Series 5W-30 in the GM turbo coking test.
  5. Based on independent testing of AMSOIL Signature Series 5W-30 in the ASTM D6593 test engine test for oil screen plugging as required by the API SN specification.
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