A pair of new diesel oil service categories from the American Petroleum Institute have been designated, and should be available by December of this year. Of particular immediate interest to farm equipment operators is the new CK-4 designation, which will supplant the long-running CJ-4 service category for diesel engine oil.

Kevin Ferrick, API’s senior manager for engine oil licensing, says the CK-4 oils offer additional protection for today’s diesel engines and are expected to be recommended by engine manufacturers for non-road diesels and diesel-powered pickup trucks currently in use.

“The CK-4 oils will be backward-compatible with CJ-4, CI-4 with CI-4 PLUS, CI-4 and CH-4 oils,” he explains. “Operators of diesel engine trucks and equipment should check with their engine manufacturers before moving up to CK-4, but most operators will learn that CK-4 is the recommended oil for their engines.”

The other service category, API FA-4, involves a distinctly different engine oil that is not interchangeable with nor backward-compatible with the familiar, traditional “C” rated diesel engine oils.

“The API FA-4 oil category is for use in truck engines designed to meet 2017 model year greenhouse gas emission standards,” Ferrick says. “API has introduced a new shaded FA-4 service symbol “donut” which is easily recognizable and distinguishes it from the CK-4 oils.”


The new Service Symbol Donut label for the upcoming CK-4 category diesel engine oil follows the standard API donut format with no shading. CK-4 oils will be backward compatible with today’s popular CJ-4 rated oils, and several others in the “C” service category.


The new API FA-4 diesel engine oil Service Symbol Donut includes a shaded category segment to help distinguish the new oils from CK-4 and other “C” rated engine oils. The FA-4 products, expected to be available in December 2016, are distinctly different, and not interchangeable with “C” series oils.

Ferrick says FA-4 oils will be multi-viscosity products in 0W30, 5W30 and 10W30 designations, but he notes the “30” in that designation is different from the “30” found in conventional “C” designated oils and automotive motor oils.

“While FA-4 oils have to meet the same requirements as CK-4 products, they are distinctly different and have specific uses that currently do not include agricultural or other off-road diesel-powered equipment,” he adds. “Also, they are not recommended for use with fuel having greater than 15 ppm sulfur and should be used only when the engine manufacturer’s recommendations call for API FA-4 oil designations.”