1990 YJ, 6 cyl..just bought today. I understand the pressure can build in the crankcase and blow back through the PVC and air cleaner. But I also read an article about the plastic valve cover leaking alot. I would like to know what anybody's experience is with this. Which one sounds like it may be the culprit? As usual, there is oil all over the valve cover and hard to tell where the leak is.. Also the aluminum valve covers tell you it will be necessary to tap a new hole in the cyl. head. NOT too crazy about that.. Should I buy a new plastic vavle cover? Thanks for your help.. Newbie to the board...
Just went through this. Take off the valve cover and see if it is cracked, mine was. If it is then buy a new one (www.4wd.com) if not then just replace the gasket as well as the PVC valve. Mine was also leaking from the cap on top of the valve cover, I used some gasket sealer and that solved that problem.
I heard that the valve cover gasket is preform, is that true?
I have the same problem! leaks @ back of valve cover and all over the bottom of the jeep, (also in the air cleaner. Whats the cure for this?) I tried to get a pvc for my 92" and they told me it's not needed or It does'nt call for one. If I have one there should be a replacement! RIGHT
Hey same problem with mine, replace the valve cover gasket, the plastic lid, (silicone) and it also leaked from the dipstick, push it on all the way, there is usually pressure under that while driving.
Your 92' should not have a plastic cover, they stopped installing them in 86', although some 87's came with them (like mine). If for some strange reason you have a plastic cover, I recommend replacing it(you'll fight this thing forever). The best replacement cover on the market is one made by Westside. It's a clean bolt in (no tapping required, however, it is somewhat costly at $160. With this cover, no gasket is used, only RTV. The job can be completed in a few hours. Note: make sure you clean the mating surfaces on the head to ensure leak free fit.