The new performance category of heavy duty diesel engine oils – American Petroleum Institute (API) categories CK-4 and FA-4, previously known as PC (Proposed Category) – are in response to federal government’s efforts to improve to fuel economy and reduce emissions in future medium and heavy duty vehicles.
API (www.api.org) is the only national trade association that represents all aspects of America’s oil and natural gas industry.
Considerable information about the new oils, will surpass current CJ-4 oil technology, can be found on VehicleServicePros.com and API’s DieselOilMatters.com.
Takeaways
Basically, CK-4 engine oils are a direct replacement for the engine oils now being used and are “backwards compatible” to all current vehicles.
The new FA-4 engine oils, offered in lower viscosity grades, are designed primarily for next-generation engines to help maximize fuel economy without sacrificing engine protection. These oils have limited backwards compatibility.
Be sure to check with your engine manufacturers about the recommended oil for your diesel engines.
Ford
At present, Ford has contacted API about concerns with certain CK-4 and FA-4 formulations causing accelerated valve train wear on its 6.7L diesel engines that hasn’t been experienced with existing CJ-4 formulations.
Consequently, it will not be recommending the use of CK-4 or FA-4 for any Ford diesel engines at this time.
In the meantime, Ford is asking API for optional/additional requirements to approve CK-4 or FA-4 formulations.