How would I be getting gas in the crankcase of my 1989 4.0 Jeep Comanche?

Answer:
One or more of your cylinders are not holding their seal.

Worn out piston rings, worn/damaged piston, worn/damaged cylinder wall are the most likely problem areas.
First answer by ID1191787680. Last edit by ID1191787680. Question popularity: 1 [recommend question].