AMSOIL Dominator 20W-50 Competition Diesel OilAMSOIL Dominator 20W-50 Competition Diesel Oil is made for racing and highly-modified street-diesel trucks. This product delivers the extra viscosity and film strength needed to protect mega-horsepower diesel engines. This might be the most cost-effective upgrade you can make for your diesel engine.

Synthetic 20W-50 Diesel Oil package sizes include:
1-Quart Bottle (or buy case of 12)
1-Gallon Bottle (or buy case of 4)

Oil Depot can offer AMSOIL Dominator 20W-50 Competition Diesel Oil at wholesale prices in Canada or the United States. Request a wholesale price list using the contact form on this page.

Suitable Applications For AMSOIL Dominator 20W-50 Competition Diesel Oil

This product is suggested for highly modified diesel engines in the following applications.

  • Modified street and off-road diesel engines
  • Sled pulls
  • Trailer tow challenges
  • Drag racing
  • Dyno performance challenges

Feature And Benefits Of AMSOIL Dominator 20W-50 Competition Diesel Oil

  • Can be used in newer or older engines.
  • Suitable for street or competition use
  • Withstands extreme loads and temperatures
  • Strong resistance to depositing and turbo coking
  • Provides exceptional film strength, even when exposed to fuel dilution
  • Pours down to -37°C for fast start-up protection

Maximum Engine Protection

Job one for Dominator 20W-50 Competition Diesel Oil is providing world-class wear control for expensive, high-output diesel engines. Nothing exploits the weakness of a motor oil more than heavy loads and extreme torque. AMSOIL loaded this product with zinc and phosphorus to maximize wear protection under severe loads.

Steady Viscosity Protection Against Fuel Dilution

High-output engines can be prone to fuel dilution. This can thin the motor oil which can reduce its ability to protect vital engine parts. Dominator 20W-50 Competition Diesel Oil’s powerful film strength withstands moderate fuel dilution. This protects expensive engine parts against metal-to-metal contact.

Protects Against Extreme Heat

Modified turbo-diesel and extreme loads can generate heat that can decimate lesser motor oils. One of the primary design features of AMSOIL Dominator 20W-50 Competition Diesel Oil is its ability to protect against exceptional heat levels. The synthetic formula is highly resistant to the depositing and turbo coking caused by extreme heat. The result is consistent protection, rock-steady viscosity and ultra-clean engine internals.

Industry Specifications Covered by AMSOIL Dominator 20W-50 Competition Diesel Oil

  • API CK-4, CJ-4, CI-4+, CH-4
  • Chrysler MS 10902
  • Ford WSS-M2C171-F1
  • Cummins 20081/20086
  • Mack EO-O/EOS-4.5
  • Volvo VDS3/VDS4/VDS4.5
  • Caterpillar ECF-2, ECF-3, ECF-1-a
  • Renault RLD-3/RLD-4

Service Life Of AMSOIL Dominator 20W-50 Competition Diesel Oil

Competition Use

Capable of staying in service for multiple heats. As the operating conditions of modified engines vary widely, use oil analysis to determine the appropriate drain interval.

Street Use

Change oil at the interval as suggested by the engine manufacturer or as indicated by oil analysis. Change oil filter at every oil change.

Mixing AMSOIL Synthetic Diesel Engine Oil With Other Brands

AMSOIL Dominator 20W-50 Competition Diesel Oil is compatible with all other brands of conventional, semi-synthetic and synthetic diesel engine oils. While you can safely mix AMSOIL Synthetic Diesel Oil with other brands, this will reduce the drain interval and performance capabilities of this product.

The use of any aftermarket diesel engine oil additives is definitely not recommended.

Specifications of AMSOIL Dominator 20W-50 Competition Diesel Oil (DCO)

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


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


Viscosity Index (ASTM D-2270)


CCS Viscosity @ -15°C, cP (ASTM D-5293)


Pour Point °C (°F) (ASTM D-97)

-37 (-35)

Noack Volatility (DIN 51581) 250°C for 1 hour, % weight loss


Total Base Number


High Temperature/High Shear Viscosity, cP (ASTM D-6481)


Sulfated Ash Content, wt. %


AMSOIL Dominator 20W-50 Competition Diesel Oil
A full-synthetic 20W-50 oil for highly modified diesel engines. Suitable for off-road, competition and street-legal diesel trucks.
Manufacturer: AMSOIL
Model: AMSOIL Dominator 20W-50 Competition Diesel Oil
Product ID: DCO