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Consumers have the freedom to choose other than OEM branded lubricants without fear of voiding the original limited or implied warranty. Amsoil synthetic lubricants and performance products are tough, reliable, long lasting, and save you time and money with the peace of mind that your vehicles/ equipment will last longer. About Warranty Secure

Diesel Engines

AMSOIL Heavy-Duty Synthetic Diesel Oil

Heavy-Duty Synthetic Diesel Oil contain advanced additives for customers seeking additional value, or oil upgrade from conventional, synthetic-blend diesel oils. Operators choose AMSOIL for its ease of maintenance (less oil changes), extreme temperature range, better diesel engine soot control and less mechanical breakdown compared to standard quality lubricants… quite simply, we don’t see equipment fail because the lubricant was too good.

The Last diesel oil specification change was 2007 when CJ-4 was introduces to deal with engines equipped with diesel particulate filters. The new specification in 2017, CK-4 is backward compatible (with CJ-4 only), while FA-4 is not backwards compatible for 2017 and newer engines. Why the new specification?… fuel economy! EPA want less emissions and better fuel economy, while manufactures are trying to manage more horsepower and torque. Newer engines produce more HP, run hotter, operate with higher boost pressure and can burn up to 20% biodiesel… all of which places a higher demand on the engine oil and specifically its wear protection.

The new AMSOIL CK-4 diesel engine oils far exceed the previous CJ-4 in performance and extended drain intervals.

Formulation change from CJ-4 to the better CK-4 diesel engine oils

  1. Oxidation resistance for viscosity stability (additional stress from engines with higher temperatures, higher horsepower and torque)
  2. Wear protection (Newer engines have higher demands on lighter oil viscosities then oil for older engines with heavier viscosities)
  3. Deposit reduction (to protect pistons, rings and cylinder liners)
  4. Dissipate heat
  5. Increased resistance to foam

Gone are the days for one spec and one viscosity. Engine technology and EPA standards have changed rapidly where oils must be applied depending on the application. If the OEM calls for a CK-4… then a CK-4 oil must be used. If the OEM allows for an FA-4 oil you have a choice; FA-4 for better fuel economy, or a CK-4 specification.

Complete lineup of AMSOIL Diesel motor oils and oil specifications

AMSOIL Newest additions to our Diesel Motor Oils:

Max-Duty Protection

AMSOIL Signature Series Diesel Oil…

Recommended for API

  • CK-4,
  • CJ-4,
  • CI-4+

*6X More Wear Protection

Heavy-Duty Protection

AMSOIL Diesel Oil…

Recommended for API

  • CK-4,
  • CJ-4,
  • CI-4+

*4X More Wear Protection

PC11 and what you need to know about API CK-4 & FA-4 Diesel Motor oils

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