Marvel Mystery Oil can be used in all pre-2007 diesel engines. 2007 and later diesel engines demand the use of Ultra Low Sulfur diesel fuel (15 parts per million of sulfur) and using higher sulfur content fuel could void your warantee. For older diesel engines designed to run on high sulfur fuel, using Marvel Mystery replaces the lubricity that is lost with the ULS diesel fuel. Use 4-ounces of Marvel Mystery Oil for each 10-gallons of gasoline. If you are using Marvel Mystery Oil in the crankcase, replace 10 % of the diesel fuel with Marvel Mystery Oil.
