When it comes to heavy-duty diesel and gasoline engines, freezing temperatures and hot weather operations call for a motor oil engineered for the extreme. Valvoline Premium Blue Extreme SAE 5W-40 Full Synthetic Engine Oil is designed for severe conditions and service. It provides performance, protection and advanced fuel economy (up to 1.5% over 15W-40 conventional oils in on-highway operation) in modern emissions treatment equipped diesel engines, including those with Exhaust Gas Recirculation (EGR) and Diesel Particulate Filters (DPF). Our superior synthetic base stocks and additive technology resists oxidation, deposits, corrosion and wear better than industry standards. No wonder it's The Only One exclusively endorsed and recommended by Cummins for both on road and off highway applications. It's specially formulated for faster and safer cold starts and has enhanced thermal properties for high temperatures during hot weather to help ensure year-round performance. Plus, extended drain intervals reduce oil changes so your engine can work longer between downtime.