Today's diesel engines are more sophisticated than ever before. Design modifications that were made to increase performance and decrease emissions have forced more soot and contaminants back into the engine. The diesel engine oil must disperse these contaminants, keep them from forming harmful engine deposits while maintaining its viscosity and providing wear protection. This is no easy feat, which is why engine oil choice has become a critical decision for equipment and fleet managers. ACDelco diesel engine oils meet and often exceed the industry's highest standards. They are formulated with only the highest quality base oils and performance–enhancing additives. Our customers can attest to their performance with testimonials of time and money savings in maintenance expenses, repair costs and downtime.