AMSOIL Signature Series 5W-20 Synthetic Motor OilAMSOIL’s Top-Tier 5W-20 Motor Oil

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Synthetic 5W-20 package sizes include:
1-Quart Bottle (or buy case of 12)
1-Gallon Bottle (or buy case of 4)
30-Gallon Drum
55-Gallon Drum
275-Gallon Tote

Signature Series stacks up against any motor oil out there. I have no hesitation in calling it the world’s best.  – AMSOIL Chief Operating Officer Alan Amatuzio on the latest Signature Series reformulation. October, 2017

AMSOIL Signature Series Synthetic 5W-20 Motor Oil is the ultimate choice for gasoline engines requiring a 5W-20. AMSOIL “ALM” 5W-20 uses an elite synthetic base oil and the finest additives to provide unsurpassed wear control, extended drain capabilities, clean operation and the best possible gas mileage.

Features And Benefits Of AMSOIL Signature Series Synthetic 5W-20

  • Will not thin out or thicken when exposed to severe heat
  • Offers ultra-long service life
  • Instant oil flow in severe cold
  • Reduces friction for optimum gas mileage
  • High TBN to neutralize acids
  • Ideal for GDI engines
  • Withstands turbocharger heat

Built For the Long Haul

One of the most remarkable features about AMSOIL Signature Series 5W-20 is its ability to stay in grade. Extreme heat and very long service intervals will not change its viscosity.

Signature Series was put through the Sequence IIIH Motor Oil Test. This test examines how resistant a motor oil is to thickening when exposed to very hot running conditions. Test oil temperatures run at 304°F (about 100°F over normal oil temperatures).

AMSOIL Signature Series thickened by just 6% over its original viscosity. The test limit is 150% above the original viscosity. The robust chemistry of AMSOIL Signature Series 5W-20 provides dependable protection over difficult and long service intervals.

AMSOIL Signature Series Viscosity Increase Graph

Provides Long Term Engine Performance

AMSOIL tested the Signature Series 5W-30 formula in a Ford F-150 turbo-charged 3.5L Ecoboost engine over 100,000 miles (160,000 km). The engine horsepower and torque were examined at the beginning and end of the trial. During the test, Signature Series 5W-30 was changed at intervals up to 25,000 miles (40,000 km). As you can see in the chart below, the horsepower and torque were virtually unchanged after 100,000 miles.

While this test was conducted with AMSOIL Signature Series 5W-30, it shares the same chemistry with Signature Series 5W-20.

AMSOIL Signature Series Horsepower Graph

Resists Deposits in GDI Engines

As auto manufacturers are striving to maximize fuel economy and power output in smaller engines, they have added gasoline direct injection (GDI) technology. GDI engines can be very prone to damaging deposits when using marginal engine oils. These deposits can cause low-speed pre-ignition (LSPI).

AMSOIL’s exhaustive testing concluded that Signature Series 5W-20 is completely immune to deposits which can lead to low-speed pre-ignition.

Elite Turbo Protection

With turbochargers becoming more prevalent than ever, motor oil technology has to keep up. The heat generated by turbos can bake motor oil into highly destructive hard deposits.
AMSOIL Signature Series Synthetic 5W-30 was subjected to the GM Turbo Coking Test. This procedure exposes a motor oil sample to 2000 heat soak cycles. In order to meet the minimum standard, the motor oil must keep internal turbo temperatures from rising above 13%. The temperature rise with Signature Series Synthetic 5W-30 was just 3.6%.

Decreases Oil Usage

AMSOIL robust formula resists volatility and shearing for exceptional resistance to oil consumption. Expect little or no oil usage in mechanically sound vehicles.

Shines In Severe Cold

This elite synthetic formula flows down to -50°C (-68°F) for unbeatable cold start protection.

Fights Acids For Long Service Life

AMSOIL Signature Series Synthetic 5W-20 has a total base number (TBN) of 12.5. This is much higher than most competing motor oils. Total base number refers to a motor oil’s capacity to combat acidity. This is one of the reasons why Signature Series 5W-20 is capable of very long service life.


AMSOIL Signature Series Synthetic 5W-20 Motor Oil is excellent for use in all types of gasoline-fueled vehicles. It is recommended for all domestic and foreign vehicles requiring any of the listed performance specifications:

  • 5W-20 (ALM): API SN (Resource Conserving), SM…
  • ILSAC GF-5, GF-4…
  • ACEA A1/B1
  • GM dexos1™ Gen 2 (supersedes 6094M) Fortified with detergents that exceed dexos1™ Gen 2 sulfated ash specifications.
  • Ford WSS-M2C945-A, WSS-M2C930-A
  • Chrysler MS-6395

Mixing AMSOIL with Other Brands

AMSOIL Signature Series Synthetic 5W-20 Motor Oil is compatible with all other brands of conventional and synthetic motor oils. While you can safely mix AMSOIL Synthetic Oil with other brands, this will reduce the drain interval and performance capabilities of AMSOIL oil.

Service Life

AMSOIL Signature Series 100% Synthetic 5W-20 Motor Oil is recommended for extended drain intervals in unmodified(1), mechanically sound(2) gasoline-fueled vehicles as follows:

• Normal Service(3) – Up to 25,000 miles (40,000 km), 700 hours of running time or one year, whichever comes first.
• Severe Service(4) – Up to 15,000 miles (24,000 km), 700 hours of running time or one year, whichever comes first.
• In all non-gasoline-fueled vehicle applications, extend the oil change interval according to oil analysis or follow the OEM (Original Equipment Manufacturer) drain interval.

(1) Engines operating under modified conditions (non-stock) are excluded from extended drain recommendations. Examples include the use of performance computer chips; non-OEM approved exhaust, fuel or air induction systems; and the use of fuels other than those recommended for normal operation by the manufacturer.

(2) Mechanically sound engines are in good working condition and do not, for example, leak or consume excessive amounts of oil, are not worn out, do not overheat, do not leak antifreeze and have properly working emissions control systems. AMSOIL recommends repairing malfunctioning engines prior to the installation of AMSOIL synthetic oils.

(3) Personal vehicles frequently traveling greater than 10 miles (16 km) at a time and not operating under severe service.

(4) Turbo/supercharged engines, commercial or fleet vehicles, excessive idling, vehicles with more than 100,000 miles (160,000 km) without prior continuous use of AMSOIL motor oil, daily short-trip driving less than 10 miles (16 km), frequent towing, snow-plowing, hauling or dusty condition driving.

AMSOIL Ea® Full-Flow Oil Filters are designed for extended change intervals. They stop smaller particles, flow more oil and last longer than regular filters. For best performance, use AMSOIL Ea Full-Flow Oil Filters.


Signature Series 5W-20 Synthetic Motor Oil (ALM)

Kinematic Viscosity @ 100°C, cSt (ASTM D-445)


Kinematic Viscosity @ 40°C, cSt (ASTM D-445)50.6
Viscosity Index (ASTM D-2270)


CCS Viscosity, cP @ (°C) (ASTM D-52934385 (-30)
Flash Point °C (°F) (ASTM D-92)

220 (428)

Fire Point °C (°F) (ASTM D-92)

244 (471)

Pour Point °C (°F) (ASTM D-97)-50 (-58)
NOACK Volatility, % weight loss (g/100g) (ASTM D-5800)5.8%
High Temperature/High Shear Viscosity
@ 150°C, 1.0 X 106 s.-1), cP (ASTM D-5481)


Total Base Number (ASTM D-2896)12.5
AMSOIL Signature Series 5W-20 Synthetic Motor Oil
AMSOIL's top 5W-20 synthetic engine oil available from Oildepot in Canada or the USA at the lowest price.
Manufacturer: AMSOIL
Model: Signature Series
Product ID: ALM