VFQuake

Just bought a 96 XJ, 200k miles. I got underneath it and noticed oil on the oil pan, and when i look up at the rear main seal, it's obviously leaking from there, but there's a small open gap between the rear main seal and the oil pan, is this normal?

I already bought everything I need to replace it, I think. Just wanting to know what you guys think.

CrawdadSlim

Let it leak, let it leak, take these words of wisdom let it leak.

XJwonders

Check the valve cover gasket and oil filter adapter, they are known to leak, and making it look like the RMS is leaking.

NCsXJ

curious as to why you say such words wouldn't you want to address a leak

F1Addict

Of course he does but maybe Crawdad had a bad experience replacing his. I've never done it but my understanding is that it's not terribly difficult. However...

^^Check these things first. Both are known to mimic an RMS leak. The bolts on the back of the valve cover (nearest the firewall) are a pain to get to and, as a result, are rarely tightened properly. If you do have to change the RMS, there's a great write-up here and an educational video here...

Part I

Part II

Good luck!

BatmanXJ

I changed mine. Only real issue was how nasty your gonna get. If you have enough lift you wont even need to use a jack. I would however make sure that the RMS is actually leaking before I went threw all that trouble.

VFQuake

Alright, I'll clean it up real good and see. I'll also try to grab a picture and post it to here.

cruiser54

I wrote this just for these threads.




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

investinwaffles

And before you touch anything, get yourself 2 cans of the heavy duty Gunk engine degreaser and go to town. Use paint brushes, Tooth brushes, wire brushes, whatever you can get your hands on to break as much of the grease as possible.

Not only helps diagnose leaks, but is essential to not getting tons of crap in your eyes and hair when you do end up working on it.

Drive it for a while and keep checking back to see which gasket is leaking.

cruiser54

Did you know that the toothbrush was invented in Boulder?

If it was invented anywhere else, it woulda been called a teethrush...........

TwoXJS

Roadrunnr72

Your bad, but in a good kind of way......RR

JackJare9455

There are 3 levels of gunk degreaser around here... the foamy, original, and heavy duty..

Every couple of weeks i grab all 3 cans ( i get it DIRT cheap) and i start with the light duty.. wash.. original... wash.. heavy duty.. wash...

I am trying to break down 17 years of washing neglect lol

it works though!!!

bubbarules1958

Dollar store oven cleaner does a better job. Just wear a mask for the fumes.

JackJare9455

Really? I will look into it... the crud built up around my starter area has not really budged even with gunk.

It built up because of a bad adapter gasket.. but that has since been replaced when I first got this XJ.

Oven cleaner... Ill put it on wifey's shopping list