Exxon Mobil announced Dec. 1 a new lineup of Mobil Delvac heavy-duty engine oils that meet the specifications of the new generation CK-4 and FA-4 engine oils, which are designed to boost fuel economy and increase oil drain intervals.
The new lineup includes Mobile Delvac 1 ESP 5W-30 (a CK-4 product), Delvac 1 Advanced Fuel Economy 5W-30 (an FA-4 product) and Delvac 1 ESP 5W-40 (a CK-4 product).
Licensing for CK-4 and FA-4 oils began last December following years of development of the new tests and specifications. The new oil categories were developed via a partnership between engine makers, oil marketers and the American Petroleum Institute, among others.
CK-4 oils replace the previous CJ-4 oils outright and are backwards compatible with all engines, though engine manufacturers ultimately decide which oils should be used in their engines. CK-4 oils are designed to improve shear stability and oxidation over CJ-4 oils and are meant to handle hotter temperatures of modern engines.
FA-4 oils, meanwhile, offer the same benefits of CK-4 oils but are designed for use in only 2017 engines and newer, though they are backwards compatible with some engines on the market, per OEM recommendations. FA-4 oils are lower viscosity oils, meaning they boost fuel economy by reducing friction of the movement of engine parts.