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New Diesel Oil Specifications Coming Soon

On December 1, 2016, two new categories of oil specifications will be licensed.  This will be the first heavy duty engine oil category change that has been made since 2007, when the CJ-4 specification was released.

Oil specifications are developed by an American Petroleum Institute committee along with subcommittees made up of industry experts including oil makers, additive suppliers, engine manufactures and other stakeholders.   This particular category development, known as PC-11, (proposed category-11) has resulted in two new oil specifications: CK-4 and FA-4.  The CK-4 engine oil will be backward compatible; however, the FA-4, to be used for certain in 2017 and newer diesel engines, is not backwards compatible.

These changes are driven by the desire for both better fuel economy and better wear protection for diesel engines.   Manufacturers are building engines that produce higher torque and horsepower output but also generate higher operating temperatures and pressures. The high horsepower, torque, and temperatures place extreme demands on engine oil.  In addition, environmental protection agencies are requiring reduced emissions and better fuel economy.

The newly specified oils provide much better engine protection than CJ-4, including: better liner protection, thermal control and shear stability, improved oxidation resistance, and reduced deposit formation.

The FA-4 oil specification is about fuel economy; you will not see the 40 grade oil in this specification.  Instead, the FA-4 specification will contain SAE XW30 grade oils.  One way to improve fuel economy is to reduce the kinematic viscosity (resistance to flow) of the oil and another is to utilize an oil with a lower HTHS (high temperature high shear) viscosity.  The FA-4 specification is for a HTHS viscosity range of 2.9 to 3.2cP (centipoise). The HTHS viscosity for the CK-4 specification is a minimum of 3.5cP. Generally, the lower the HTHS viscosity number the better the oil contributes to fuel economy.

AMSOIL corporation’s synthetic diesel engine oils meeting the CK-4 and FA-4 specifications will be available in early 2017, in the meantime take a look at all of AMSOIL's current diesel products.