I am used to running an SAE 40 weight (or 15w-40). Can Delvac 1 be used as a replacement for all 40 weight oils?
“All 40 Weight Oils” is a very broad category. Delvac 1 can be used in engines that call for a 40 weight straight grade or multi-viscosity grade oil meeting API CI-4, CH-4, CG-4, CF-4, CF or CE quality levels. Delvac 1 can be used in engines calling for Mack EO-N, Mack EO-M Plus, EO-M, EO-L Plus or EO-L and Cummins 20078 or CES 20076. Delvac 1 can also be used in gasoline engines that call for an SL, SJ, SH, SG or SF quality oil. That covers a lot of engines. Delvac 1 is NOT the primary recommendation for Detroit Diesel two-stroke cycle engines (Series 53, 71, 92, 149) which require an SAE 40 mono-grade engine oil. If you are not sure if Delvac 1 is appropriate for your application, call the Mobil Customer Response Center at 1-800-662-4525.