We all get tired of the oil film/leak on top of our 4.0 Jeep aluminum valve covers. Many times the biggest culprit is the loose fitting oil filler cap. Here’s a real easy fix:
- Remove the plastic oil filler cap and wrestle the original rubber gasket from it using a small pick or screwdriver.
- Make a duplicate of the gasket out of an old bicycle inner tube using scissors and a knife or razor blade.
- Install the duplicate on the cap first, and then the original over top of it.
It will be a tight fit on the valve cover the first time, and may require some persuasion with a pair of pliers, but will get easier with time.