As diesel engine designs evolve, so do the oils needed to lubricate those engines. The current industry standard, API CJ-4, was introduced in 2006. Two new diesel engine oil specifications will replace API CJ-4 and become the new OEM recommendation in December of 2016.
- CK-4 will replace CJ-4 with the same minimum High Temperature/High shear (HT/HS) viscosity of 3.5cP and is backwards compatible for on road diesel engines build prior to model year 2017.
- FA-4 is a new fuel efficient standard with a High Temperature/ High Shear (HT/HS) viscosity between 2.9 and 3.3cP, and is recommended for 2017 on raod diesel engines. (FA-4- Think Fuel Efficient for the F and this is the very first release of this new standard, so A is appropriate. 4 for 4 Stroke.) The new FA-4 specification is NOT backward compatible.