A. Diesel heavy duty engine oils that meet the current American Petroleum Performance Category CJ-4 are backward compatible with older engines such as yours and provide additional performance benefits compared to oils of the late 1990's.
1. My question for reference is what are you currently using by brand, product name and viscosity-I assume 15W-40?
2. Are you having any engine problems or problems that you believe to be lubrication related?
3. It is also always important to know, your engine make and models, about your operating conditions, lubrication service intervals and maintenance goals when making recommendations As an initial recommendation, I will recommend the CITGARD 600 15W-40 engine oil, that not only meets CJ-4 but also meets all major diesel engine builder specifications and it comes with the CITGO LubeAlert Oil Analysis program.