Effective from dec 1st 2016. New API heavy duty specifications CK-4 and FA-4.

Coming into effect: The new specifications API CK-4 and FA-4

2016 may be in the past, but another change is in the making. New API specifications for the category 11 oils (PC-11) became effective as of December 1st.

These new specs are in place of the CJ-4 classification, there being a split category for High Temperature High Shear viscosity grades (HTHS). Given the division of the categories, knowing the difference between the two becomes crucial.

The differences between API CK-4 and FA-4 and what they mean

For use in heavy-duty diesel engines, the new CK-4 oils will influence oil selection for models of large diesel engines old or new, including those used in agriculture or construction that are not normally highway vehicles. 

While accepting that both oils can be used in engines both old and new, CK-4 oils are specially created to be interoperable with older systems and are engineered for high HTHS engines (at least 3.5 cP), whereas FA-4 oils are intended for more recent and modern engines (between 2.9-3.2 cP).

The manufacturers’ specifications for specific engines should be something that owners and oil suppliers are up to date with, but it is advisable to regard FA-4 initially for more recent engines.

The two specifications’ dissimilarities are indicated by their labels.

API have introduced a specific label to mark the difference between the CK-4 specification and the FA-4. A red shaded segment appears in the emblem for the FA-4:

Why the change?

While the old engine oil was adequate in its period, changing rules and customer requirements for enhanced fuel saving and engine reliability have provoked the transformation. This transformation is the result of nearly nine years of evolving new standards, its intention being to enable market forces to carefully examine and test the new capabilities of the classifications. 

The update notes the differing requirements of both modern and older diesel engines. 

Representing a marked advance over CJ-4, the CK-4 oils will offer wide scale protection including a complete range of factors such as oxidation, shear stability, engine deterioration, and deposits. It is intended for engines using diesel fuel with a sulphur content up to 500ppm. FA-4 oils are intended to satisfy the requirements of 2017 model engines with the more stringent greenhouse gas emissions restrictions and use fuels with sulphur content below 15ppm. 

This category split is intended to satisfy the emissions control requirements of more modern engine designs and after treatment systems. If you use fuel applications above 15ppm sulphur, FA-4 oils are the wrong choice.

As always, refer to manufacturers’ recommendations when assessing the requirements of your engine oil.

Summary:

• CK-4 oils replacing CJ-4 oils, interoperable with older systems.
• FA-4 oils replacing CJ-4 oils, no specific interoperable capabilities.
• Marked advances concerning oxidation resistance, aeration, fuel consumption and shear stability
• Taking into account the specification split, knowing the difference between the two is vital.