wingit

I replaced the rear crank seal in Feb of this year. I have put almost 10,000 miles on it since then and the seal is now leaking again. I took a thousand mile trip last week and when I got back I noticed it was leaking. Any idea why this would happen so soon? Jeep has 97,000 miles on it.

wingit

Anyone else experienced this?

cruiser54

Are you 100% sure it's the RMS?

I wrote this years ago for just such situations:




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

Roler

I was thinking a similar thing.
If the installation of the RMS was faulty for some some reason, or the area it sits was damaged in the proces of installing it, it would likely show leaks very soon after the job was done, I'd reckon. Or the quality of the seal must have been reeealy crap...

wingit

So the oil leaking was coming from a brand new after market oil plug drain. I used a copper washer with this and don't think I needed too. Purchased factory oil plug and no more leak.

cruiser54

That was easy.

steelybill

I should be so lucky.....to fix one like that..