In late October of last year, OEM/Lube News was advised by Ford Motor Corporation that the company does not recommend the use of API CK-4 nor FA-4 oils in any of its diesel engines. Ford stated it recommends oils that meet Ford Material Engineering Specification WSS-M2C171-F1, in lieu of CK-4.
Last December, the American Petroleum Institute (API) began licensing the two new diesel motor categories CK-4 and FA-4. API CK-4 was released to replace CJ-4. FA-4 is a low viscosity diesel oil released for diesel engines designed for a lower viscosity oil. Ford Motor stated that, due to its low viscosity, API FA-4 oils should not be used in any Ford diesel vehicles at this time.
A Ford Motor Company spokesperson told OEM/Lube News "Motorcraft/Ford Motor Company does not have an engine that uses now or in the near future will use FA-4. Therefore Motorcraft has no oil or plans for an oil that meets FA-4."
As stated above, Ford said it does not recommend the use of CK-4 motor oils in any Ford diesel engines, new or old. Testing Ford has done on some CK-4 formulations have shown inadequate wear protection compared to CJ-4 formulations developed and licensed before 2016.
Like many other diesel engine manufacturers, with their own internal OEM specification, Ford recommends oils that meet an OEM specification, Ford Material Engineering Specification WSS-M2C171-F1, like Motorcraft Super Duty Motor Oil, and that the customer/Ford owner customer should use an oil showing that it meets this specification.
Ford further stated that 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. Field experience and Ford testing has shown that these older CJ-4 formulations provide acceptable 6.7L engine protection.
Ford stated that certain CK-4 oils may meet WSS-M2C171-F1 specification, but each oil would need to be approved separately for use in Ford diesel engines.
In December 2016, Ford issued a list of over 200 motor oils it had determined acceptable for use in its diesel engines. The list included SAE 5W-40, 10W-30, 10W-40 and 15W-40 viscosity oils, all meeting Ford WSS-M2C171-F1 specification.
Ford has now updated the list. To see the latest list of Ford approved diesel engine oils, click here