WASHINGTON, D.C. – The new CK-4 and FA-4 categories of heavy-duty engine oils are coming to the market Dec. 1, reminds the American Petroleum Institute (API).

“Dec. 1 is an industry milestone as it marks the first day new API CK-4 and FA-4 engine oils can be marketed and sold on retail shelves or in bulk,” said Kevin Ferrick, senior manager of API’s Engine Oil Licensing and Certification System (EOLCS). “The time between approval of the categories last winter and the first licensing on Dec. 1 gave large, medium, and small oil marketers the ability to test their new formulations and ready them for market. This signals the culmination of almost nine years of cross-industry collaboration in the development of the new standards.”

API CK-4 oils will replace current CJ-4 engine oils and will be backwards compatible with most applications in which CJ-4 is used today. They’ll offer improved shear stability, oxidation resistance and aeration control, the API claims.

API FA-4 oils will provide similar improvements, but are only intended for use in newer on-highway diesel engines, API says. The organization says technicians and end users will need to check their owner’s manuals to determine which oil is most appropriate for their vehicle.

API developed two visually different API Service Symbol Donuts so that consumers can easily distinguish between the two categories. The new API FA-4 donut features a shaded section to differentiate API FA-4 oils from CK-4 oils. The API CK-4 donut will look the same as the current CJ-4 donut.