Question about 1990 Jeep Wrangler

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Engine blowing oil from oil filler cap

1990 jeep yj 2.5L engine blows oil from under oil filler cap. when I remove the cap while engine is running it lets air out.appears to be building back pressure. replaced pcv no help. big oily mess under hood. engine does not smoke the usual blue smoke if rings were bad also dosen,t smoke when cranked after sitting over nite.

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I had the same problem. I changed the pcv valve and checked the hose. It still did the same thing. Then I checked the metal tubing that the hose connects to and found it was full of hardened gunk. I sprayed PB Blaster into the tube let it soak for awhile. Then took an old choke cable, put it on a drill and ran it into the tube like a drain snake. It took a while of doing this over and over but eventually got it cleared out. Now, no more oil all over the engine and hood compartment.  

Posted on Mar 21, 2009

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If you have changed the pvc valve with no success you should check the breather hose to the manifold. Also check that the hole is clear in the fitting on the manifold that the hose goes onto. Failing that its most likely the rings I'm afraid. A cylinder leakage test would be the best way to check this but is specialist equipment. No more than 15% leakage is normal

Posted on Dec 12, 2008


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