Specific Gravity of Diesel Fuel VS Motor Oil
The reason for the question is....in the event of an injector not closing properly and letting fuel leak into the cylinder will diesel fuel float on motor oil or is it reverse?
Forum Discussion
Yup. It mixes. If your motor start "making" motor oil, time to dig deeper. It can tolerate some dilution, but not much. On out '08 Cummins 6.7L trucks, we had to switch to 4,000 mile oil changes due to oil dilution. On our case, the excess fuel was from the trucks being frequently in Regen mode. Cummins uses the regular injectors to dump extra fuel into the cylinders so it burns off in the DPF.
