The American Petroleum Institute (API) is introducing two new standards to take into account the latest technology in diesel engines. API CK-4 and FA-4 will first appear in the API service symbol donut on Dec. 1, 2016. These new service categories improve upon existing standards by providing enhanced protection against oil oxidation, engine wear, particulate filter blocking, piston deposits, and degradation of low- and high-temperature properties.
API CK-4 describes oils for use in high-speed, four-stroke-cycle diesel engines designed to meet 2017 model-year on-highway and Tier-4 non-road exhaust-emission standards as well as for previous model-year diesel engines. These oils are formulated for use in all applications with diesel fuels ranging in sulfur content up to 500 parts per million (ppm). However, the use of these oils with greater than 15 ppm sulfur fuel may impact exhaust aftertreatment system durability and/or oil drain intervals.
CK-4 oils exceed the performance criteria of API CJ-4, CI-4 with CI-4 Plus, CI-4, and CH-4, and can effectively lubricate engines calling for those API service categories. When using CK-4 oil with higher than 15 ppm sulfur fuel, consult the engine manufacturer for service interval recommendations. Most truck manufacturers recommending API-licensed CJ-4 engine oils will likely recommend truck owners start using licensed API CK-4 oils as soon as they are available.
The API FA-4 standard designates certain lower viscosity oils specifically formulated for use in select high-speed, four-stroke-cycle diesel engines designed to meet 2017 model-year on-highway greenhouse gas (GHG) emission standards. Some engine manufacturers might recommend FA-4 oils for their previous model-year vehicles, but it is more likely that manufacturers will recommend the oils starting with the 2017 model-year engines. These oils are neither interchangeable nor backward compatible with API CK-4, CJ-4, CI-4 with CI-4 Plus, CI-4 or CH-4 oils. Therefore, you should heed the engine manufacturer’s advice for API FA-4 oils.