Late last fall, API introduced two new diesel engine oil standards —
CK-4 and FA-4. First licensing of these oils was December 1, 2016.
What’s the difference between the two oil standards? CK-4 engine oils are a direct replacement for CJ-4 oils. The new FA-4 engine oils are offered in lower viscosity grades and are designed primarily for next-generation engines — found primarily in over-the-road trucks — to help maximize fuel economy without sacrificing engine protection. FA-4 oils have limited backward compatibility, but won’t be widely found in our industry anyway.
CK-4 and FA-4 are bright, shiny and new, but not everyone is excited about them. Ford has actually issued a position statement on the oils. Why?
According to Steve Swedberg’s article “It’s Always Something” in the January 2017 edition of Lubes and Greases magazine, “Ford has seen accelerated valve train wear in their 6.7L engines with some CK-4 and FA-4 formulations with less than 1,000 parts per million phosphorus that they haven’t seen with CJ-4 oils. Based on these results, Ford has wear concerns about CK-4 and FA-4 in both new and older Ford engines.”
The Updated Ford Motor Company CK-4/FA-4 Ford Position Statement said, “Due to its low viscosity FA-4 should not be used in any Ford diesel vehicles at this time.”
It continued, “Ford will not be recommending the use of CK-4 motor oils in any Ford diesel engines, new or old. Ford testing has shown some CK-4 type formulations have shown inadequate wear protection compared to CJ-4 formulations developed and licensed before 2016.
“Ford now recommends using oils that meet our OEM specification, Ford Material Engineering Specification WSS-M2C171-F1. … WSSM2C171-F1 contains all the requirements of CK-4 with additional Ford requirements for added engine protection.
“For a short period of time, an oil showing CJ-4 in the API donut, without showing CK-4, would be acceptable for service even if not showing WSS-M2C171-F1. This oil would most likely be an older CJ-4 formulation, developed and licensed prior to 2016. Years of experience and Ford testing has shown that these older CJ-4 formulations provide the necessary engine protection in all Ford diesel engines where CJ-4 and older C categories are recommended. Some of these CJ-4 oils could be available for up to a year after December 1, 2016.”
Ford warns that customers and installers should not use oils labeled CK-4/SN unless they have been approved by Ford Motor Company to meet WSS-M2C171-F1. These oils will possibly be found in SAE 10W-40, 15W-40, 5W-40 and 0W-40 viscosities. At this time, according to Ford, SAE 10W-30 oils showing CK-4/SN cannot meet WSSM2C171- F1 and should be avoided.
You can check the Motorcraft website for diesel motor oils approved by Ford Motor Company for servicing Ford diesel engines:
If you would like to find out more information about the CK-4 and FA-4 diesel oil specifications, here are some resources you might find helpful: