Even 10% gasoline mixed with diesel is not considered safe, especially in a modern diesel engine.

At 10%, gasoline can:

  • Significantly reduce fuel lubricity and viscosity.
  • Damage the injection pump and injectors.
  • Cause knocking, rough running, power loss, overheating, or stalling.
  • Lower the fuel’s flash point and increase fire risk.

An older mechanically injected diesel might appear to run on the mixture, but damage can still occur. I would recommend no gasoline at all. For processed waste oil, dilute it only with clean diesel fuel.