I have 92 Jeep Cherokee with a 6cyl 4.0L engine. It leaks a lot oil from the dipstick, but not when it's idling. It does seem to change oil pressure quite a bit as the RPMs change. It's not overfilled. What would cause it to leak oil like that from the dipstick?
Blow-by. Bad rings leaking combustion pressures into the crankcase and oil pan, blowing oil out the dipstick. Pull the spark plugs and perform a compression test to verify which cylinder is leaking. If the cylinder walls aren't damaged, you can perform the repair yourself. You'll need a Haynes or Chilton's Motor Manual and a handful of tools and parts.
June, 15, 2011 AT 5:16 AM
You might also check your PCV system, the vacuum hose may have come loose, or the PCV pulled out. You are at the correct oil level, not overfilled?
June, 15, 2011 AT 6:27 AM
Thanks for the info. I did make sure it was not overfilled. My daughter wanted this model and we found this one a few months ago real cheap because it needed an engine. An ex-neighbor of ours convinced my wife that we should use her mechanic because I didn't have time to do the work as fast as my daughter wanted.
He put a used engine in it and delivered the car with a broken intake manifold, power steering pump bracket, and with a wire harness draped over the exhaust pipe that melted and caused a short. Of course he claimed he didn't cause any of the problems. BBB and the BAR is now involved and I've been correcting his shoddy work ever since. It's been leaking oil since we've been able to drive it so I'm sure he never really checked the engine like he claimed.
It's been about 10 years since I've done any major engine work like this, but I'll do it right and my daughter will just have to wait until I'm done.
Maybe I'll do it right and rebuild the whole thing. : -)
June, 15, 2011 AT 6:35 AM
CJ is right, it *COULD* be the PCV vslve, but I'd lay odds on rings. Do a compression test. That'll be the tale of the tape there. If you find a hole with low compression, do a wet test on it. If it jumps up, you got your culprit: rings. Not a hard fix, just time consuming. Good luck and let us know how it goes, ok?