The best diesel oil for an engine depends on the type of vehicle and how often the oil is changed. However, most diesel engine oils should be heavy-duty, fully synthetic products designed with high performance in mind.
Owners of a diesel car or truck need to select oil specifically designated for use with diesel engines. There are several brands that may be beneficial to such owners. One example, from carsdirect.com, is an oil that only needs to be changed once a year, and can last for up to 25,000 miles. The same source also notes that there are quality diesel engine motor oils that perform well at various temperatures. Diesel truck owners should note that there are several brands that meet or pass recommendations from diesel truck manufacturers along with government regulations.
Individuals with older vehicles can still find specific oil for a diesel car or truck. Examples include oils designed for use with turbo engines and high-speed four-stroke naturally aspirated engines dating to the 1990s.
When choosing diesel oils, carbibles.com notes, the first letter is C. In diesel oils, CJ is currently the highest grade on the market. However, CH is also popular and works well with passenger vehicles.