Questions and Answers

Petrol Mixing With The Engine Oil Q. Greetings!! I'm a person that has problems with his car. The problem is this: My car has started to mix the petrol with oil inside the motor and nobody can fix that problem. I've been to many mechanics but they don't know to fix it. I wonder if you can help me, but if you don't I think my car will be blocked by short time. Thanks...

A. The only way fuel can get into the oil is through the cylinders. A clogged injector won't do it, but one that doesn't close completely will.

The fuel injectors face the back of the intake valves which point down. If an injector is leaking, and the valve is open, fuel can enter the cylinder and seep past the rings into the crankcase. The same thing can happen with a carburetor that has an internal leak.

This can be confirmed by putting a fuel pressure gauge on the fuel rail and running the engine to get full fuel pressure. Shut the engine off and immediately pinch the fuel feed and return lines. If the fuel pressure drops, you have an injector(s) leaking into the cylinder(s).