100% synthetic, high-performance oil that meets and exceeds the latest diesel emission requirements and all other heavy-duty diesel engines. Central Petroleum Company (CEN-PE-CO) is one of the oldest and largest independent oil compounders in the United States. This means we blend our own oil. We have the ability to obtain the highest-quality ingredients (components) available, blend them together and market them under our exclusive Cen-Pe-Co brand name. Cen-Pe-Co has been in business since 1911, marketing products directly to the heavy-duty equipment user. MADE IN THE USA     Extreme Duty 5w40 Engine Oil is a premium quality lubricant designed for use in heavy-duty diesel engines. This motor oil is specifically formulated to provide superior protection and performance under the most demanding operating conditions. The Extreme Duty 5w40 Engine Oil is made using high-quality synthetic base oils and advanced additive technology, which provides excellent protection against wear, corrosion, and deposit formation. Its viscosity is carefully selected to provide outstanding performance in both high and low-temperature environments, ensuring the engine stays lubricated and protected under all conditions. This motor oil is suitable for use in a wide range of heavy-duty diesel engines, including those fitted with exhaust gas recirculation (EGR) systems and diesel particulate filters (DPF). It is recommended for use in vehicles operating in severe-duty applications, such as long-haul trucking, construction, and agriculture. The Extreme Duty 5w40 Engine Oil is easy to use and compatible with all conventional and synthetic motor oils. It meets or exceeds the requirements of many leading engine manufacturers, including Caterpillar, Cummins, and Detroit Diesel. Overall, Extreme Duty 5w40 Engine Oil is an excellent choice for anyone who demands the best performance and protection for their heavy-duty diesel engine. Its high-quality formulation and compatibility make it an excellent investment for fleet operators, owner-operators, and anyone who wants to maximize the performance and lifespan of their diesel engine.