AMSOIL Signature Series 100% Synthetic 5W-30 Motor OilAMSOIL’s Finest Synthetic 5W-30 Motor Oil. Buy AMSOIL 100% Synthetic 5W-30 Motor Oil at the lowest price in Canada and the USA. Request a wholesale price list with the form on this page. Read more about the new formula.

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

Independent Testing of AMSOIL Signature Series Synthetic 5W-30

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’s best 5W-30 Motor Oil is engineered to outperform regular engine motor oils by a wide margin. This professional grade synthetic formula reduces heat, friction and wear for maximum power, performance and fuel efficiency. AMSOIL ASL 5W-30 is ideal for gasoline engines in hot and cold climates.

Features And Benefits Of AMSOIL Signature Series Synthetic 5W-30

  • Maintains original viscosity over ultra-long service intervals
  • Highly resistant to extreme heat and heavy loads
  • Flows down to -50°C (-58°F) for cold start-up protection
  • Reduces friction for maximum fuel economy
  • High TBN to fight acids, extend service life
  • Will not generate deposits in GDI (gasoline direct injection) engines
  • Outstanding turbocharger protection

Maintains Viscosity For Entire Service Life

One of the most impressive features of AMSOIL Signature Series Synthetic 5W-30 is the ability hold its original viscosity over the entire service interval. It is all but impervious to thickening or thinning out over ultra-long periods. Even after 25,000 miles (40,000 km) of operation, Signature Series 5W-30 holds its original viscosity.

The Sequence IIIH motor oil test shows how well a motor oil can endure extreme heat. This test is performed at oil temperatures held at 304°F. This is roughly 100°F above normal operating oil temperatures.

Sequence IIIH testing shows that the viscosity of AMSOIL Signature Series thickened to just 6% above its brand-new viscosity. The Sequence IIIH test limit is 150% above the new viscosity.

AMSOIL Signature Series Viscosity Increase Graph

Preserves Engine Performance And Minimizes Wear

AMSOIL tested Signature Series 5W-30 in a Ford F-150 3.5L Ecoboost turbo-charged engine over 100,000 miles (160,000 km). The engine horsepower and torque was measured at the beginning and end of the test. During the test period, the 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 engine output remained all but unchanged after the long-term test. Signature Series offers wear control that is 75% better than the API SN industry benchmark. This is truly world-class wear protection.
AMSOIL Signature Series Horsepower Graph

Ideal For GDI Engines

Many modern cars and truck engines employ gasoline direct injection (GDI). GDI engines can be very prone to engine deposits which can lead to low-speed pre-ignition (LSPI). Extensive testing shows that AMSOIL Signature Series 5W-30 resists engine deposits so thoroughly that it provides 100% protection against LSPI.

Dependable Turbo Protection

Turbo-chargers generate extreme heat and are a very hostile operating environment for a motor oil. Hot turbo-chargers can bake motor oil into hard deposits that can destroy turbo bearings.
AMSOIL Signature Series Synthetic 5W-30 was put through the GM Turbo Coking Test. This test subjects a motor oil to 2000 heat soak cycles. A passing grade requires that a motor oil keep internal turbo temperatures from rising beyond 13%. Signature Series Synthetic 5W-30 curbed the temperature increase to just 3.6%. This is 72% better than the limit for the GM dexos2 Gen 2 specification.

Delivers Maximum Fuel Economy

AMSOIL Signature Series Synthetic 5W-30 Motor Oil’s synthetic formula delivers exceptionally low friction for the best possible gas mileage and smooth operation.

Cuts Oil Usage

AMSOIL Signature Series Synthetic 5W-30 is highly resistant to volatility during hot operating temperatures. The low volatility prevents oil burn-off and promotes clean engine internals. This also greatly reduces varnish and deposits.

Instant Cold Start Protection

Regular engine oils are no match for AMSOIL 100% Synthetic 5W-30 in extreme cold. The -50°C (-58°F) pour point means instant oil flow during cold start-ups.

AMSOIL Signature Series Cold Pour Point Graph

High TBN Fights Acid

AMSOIL Signature Series Synthetic 5W-30 has an exceptionally high total base number (TBN) of 12.5. A high TBN number means that this motor oil has a strong capacity to fight acidity. This also contributes to Signature Series 5W-30’s ability to stay in service for far longer than other synthetic and conventional motor oils.


AMSOIL Signature Series Synthetic 5W-30 Motor Oil is suitable for all cars and trucks with gasoline engines requiring the following industry specifications:

  • API SN (Resource Conserving), SM…
  • ILSAC GF-5, GF-4…
  • ACEA A5/B5, A1/B1
  • Ford WSS-M2C946-A, WSS-M2C929-A
  • Honda HTO-06
  • Chrysler MS-6395
  • GM dexos1™ Gen 2 (supersedes LL-A-025, 6094M and 4718M) Fortified with detergents that exceed dexos1™ Gen 2 sulfated ash specifications

Mixing AMSOIL with Other Brands

AMSOIL Signature Series Synthetic 5W-30 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-30 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 100% Synthetic 5W-30 Motor Oil (ASL)

Viscosity @ 100°C, cSt (ASTM D-445)


Viscosity @ 40°C, cSt (ASTM D-445)


Viscosity Index (ASTM D-2270)


VISC. CCS, cP (ASTM D-5293)

3968 (-30)

Flash Point °C (°F) (COC) (ASTM D-92)

220 (428)

Fire Point °C (°F) (COC) (ASTM D-92)

244 (471)

Pour Point °C (°F) (ASTM D-97)

-50 (-58)

NOACK (% weight loss) (ASTM D-5800)


High Temperature/High Shear Viscosity
@ 150°C, 1.0 X 106 s.-1), cP (ASTM D-4172B)


Total Base Number (ASTM D-2896)


AMSOIL Signature Series 5W-30 Synthetic Motor Oil
AMSOIL's premiere 5W-30 Synthetic Engine Oil available for sale in Canada and the United States from Oildepot.
Manufacturer: AMSOIL
Model: Signature Series
Product ID: ASL