I have a 1995 jeep cherokee and it has he worst oil leak...it started leaking after I put the new engine in it (1991). I heard it was the rear main seal but I don't know what to do or how much time/experience is needed?

Remove the oil pan with your next oil change. Try a new gasket for $17.

If that doesn't work, then look at the seal.

I replaced all of my rod bearings in under 4 hours.

Hell, if you're gonna' go through all the trouble of taking the oil pan off, just replace the rear main seal while you're in there. Add an hour of your time, kill two birds with one stone, and then you'll know for sure, instead of having to take the oil pan off a second time.

http://jeep-xj.info/HowtoRearMain.htm

Whoa!!!!!!

Verify the source before diving in. Are you a glutton for punishment?




I'd be looking up ABOVE first, and VERIFYING the source of the oil leak YOURSELF.

Everybody, who doesn't own or have to pay for or perform your vehicle repairs, loves to poke their noggin UNDER the Jeep and come out bearing the false bad news that your RMS is leaking.

Many mechanics, friends, people on Jeep forums who can’t see your Jeep from where they’re at, and good old Uncle Bob seem to enjoy telling you it’s the rear main seal. Has a catastrophic ring to it, doesn’t it?

A simple leak at the back of the valve cover or other source could produce the same symptoms. You don’t need to be a mechanic to figure this out. If you have good eyesight and a dim flashlight, you’re good to go on your own. Don't jump on the RMS/oil pan gasket bandwagon right off the bat.

Almost any oil leak on your 4.0 is gonna drip from the RMS area for two simple reasons.

First off, the engine sits nose-up and any oil will run back to the RMS area. Secondly, the RMS area is also the lowest point on the engine. Simple physics and the old plumber's adage apply here. "$hit flows downhill".

Valve cover gasket, oil pressure sending unit, oil filter adapter seals and distributor gasket, in that order, have to be eliminated as possibilities first.

Revised 02-26-2013

COME ON GUYS!!!!!!

What????????????????

You give this kind of advice to a guy who is unsure of where his leak is and admits he has limited mechanical knowledge/ability?

I'm with Cruiser, do the steps. Don't just go off thinking its the RMS do some noggin poking..
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First off, the engine sits nose-up and any oil will run back to the RMS area. Secondly, the RMS area is also the lowest point on the engine. Simple physics and the old plumber's adage apply here. "$hit flows downhill".

Valve cover gasket, oil pressure sending unit, oil filter adapter seals and distributor gasket, in that order, have to be eliminated as possibilities first.

I was told by a mechanic that my RMS was leaking when he was looking at my exhaust for me 2 days after I bought my XJ. I had been reading on this forum for some time before I bought my XJ and had saw this posted before......So off to the car wash I went $9 worth on the engine above and below, everything was oily and dirty under the hood. Drove it home 7 mi. some at highway speeds 65 mph and about all the water was gone or dried up where I had washed.

Up on the jack stands it went for an inspection and sure enough it "WAS NOT" the RMS but the Oil Filter Adapter housing that was leaking and the valve cover was loose the gasket was fine. It was one of those $7 O-Ring deals and tighten the valve cover bolts to tq. specs. all done no more oil leaks period when the oil/filter change was finished.

Thanks to the posts I had been reading here before I ever had bought my XJ I knew where to start looking for oil leaks.

Thanks for posting that up Fred.

Your experience mimics many others. That's exactly why I wrote my goofy little diddy on RMS replacement.