Mobil Delvac 1™ 5W-40 is a fully synthetic high performance heavy duty diesel engine oil that helps towards long engine life while providing long drain capability for modern diesel engines operating in severe applications. Mobil Delvac 1 5W-40 delivers excellent performance in modern low emission engines, including refrigerated units, as well as older, well-maintained engines. Mobil Delvac 1 5W-40 is recommended for use in a wide range of heavy-duty applications and operating environments found in the on-road transport and off-road mining, construction, and agricultural industries. Mobil Delvac 1 also meets the requirements of the API SL specification for gasoline engines used in mixed fleets. The excellent performance of Mobil Delvac 1 5W-40 is the result of extensive cooperative development work with major equipment builders and application of advanced lubrication technology.