In late October of 2016, 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. Testing Ford has done on some CK-4 formulations have shown inadequate wear protection compared to CJ-4 formulations developed and licensed before 2016.
Also, 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, new or old. 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."
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. SAE 10W-30 and 15W-40 are the most predominant with only one each SAE 0W-40 and 5W-30 approved.
Ford has now updated the list which includes approximately 375 acceptable oils. To see the latest list of Ford approved diesel engine oils, click here