What does API CJ-4 mean?
What does API CJ-4 mean? API Service Category CJ-4 describes oils for use in high-speed four-stroke cycle diesel engines designed to meet 2007 model year on-highway exhaust emission standards as well as for previous model years. Oil Interchangeability Guidelines and the API Guidelines for SAE Viscosity-Grade Engine Testing. Is SAE 30 Good for diesel engines? SAE 30 Motor Oil is recommended for use in older two- and four-stroke diesel engines where the SAE 30 engine oil is specified by the OEM. Protection against rust, corrosion, varnish, and sludge — Helps keep oil screens, filters, and rings clean and free for...