Ghost Lubricants DCORE Diesel Engine Oil is a high-quality lubricant designed for all diesel-powered equipment, on-highway and off. It’s a pure-performance-booster in tractor-trailers, buses, dump trucks, delivery trucks or generators, whether your operations are coast-to-coast, state-to-state, or in or around town. DCORE’s advanced fully synthetic formulation with high-powered additives meets the toughest greenhouse standards, while delivering precise lubrication to the smallest engine parts and extending engine life in the toughest conditions. It’s finally here—a diesel oil as versatile and hard-working as your job demands. Improve MPG. Improve horsepower. Improve performance. Improve on lessening emissions with GHG-17 Compliance.