The new donut features a shaded section to differentiate API FA-4 diesel oils from CK-4 oils. The API CK-4 Service Symbol Donut will look the same as the current CJ-4 Donut.

I f you've ever bought a quart of motor oil for your vehicle, you've likely encountered the letters API somewhere on the label. In fairness, there are a lot of abbreviations, symbols and odd ...

WASHINGTON, D.C.– The American Petroleum Institute (API) is introducing a new special Service Symbol Donut to help consumers identify the recently approved API FA-4 diesel engine oil. API approved two ...