Mysterious oil leak-Your thoughts?

[BombThreat]

I don't think this would be all too mysterious to some people but for me it's got me a little confused. My yj has had this steady oil leak and a couple days ago I figured I was going to stop it once and for all with replacing the rear main seal (along with the oil pan gaskets). And even after doing that I'm still getting the same leak. Although now that I cleaned that arear up a bit I can better see where the leak is accully coming from and its dripping from the inside of the clutch housing. (eh?). And just to the left where the starter bolts up, its leaking from there too. What do you guys think could be the cause of this? Could it be a bad bearing and seal... Something? Your thoughts are appreciated.

By the way, the specs of my jeep are; 1991 Wrangler, 5-Speed, with a 4.0L engine.

[Rock WoRM]

Have U checked your valve cover gasket? Sometimes they can leak pretty bad @ the rear and U don't know it.

WoRM :bsod:

[wcjp]

I agree with the valve cover gasket. Do yourself a favor and buy the factory rubber gasket. I did the aftermarket cork. Still leaks.

[BombThreat]

Ha, I forgot the mention I just replaced the valve cover gasket yesterday. And I did use the cork one:( Although. This very well might have been the issue. Because as I was taking the cover off, every single bolt was finger tight or worst. Also noticing alot of nasty oil/gunk to the rear of the engine. Ill have to park it on the pavement and see if she's still leaking after that. Oh and maybe this helped, when I put the cork gasket on, I also applied some indian gasket sealer on both sides.

[Jays89YJ]

Ha, I forgot the mention I just replaced the valve cover gasket yesterday. And I did use the cork one:( Although. This very well might have been the issue. Because as I was taking the cover off, every single bolt was finger tight or worst. Also noticing alot of nasty oil/gunk to the rear of the engine. Ill have to park it on the pavement and see if she's still leaking after that. Oh and maybe this helped, when I put the cork gasket on, I also applied some indian gasket sealer on both sides.
Bomb, the cork gasket does work. Did you use a gasket scraper on both surfaces to remove the rest of the junk? If you did you should be fine. Just make sure you get the engine nice and hot and let it cool. Then torque down those bolts again. Pressure wash the engine and keep a close eye on it to see where it's coming from.

[Rock WoRM]

Here's another thought... could it be coming from the front of the tranny?

WoRM :bsod:

[BombThreat]

I checked out to see if its still leaking and it is. So It's neither the rear main seal or valve cover. Any other ideas?

[nobelstephan]

Try using the vavoline oil engine for over 75,000 miles. It stopped the leaks on my Jeep's engine. The oil has additives that rejuvenate and swell the seals. (got it from Wal-Mart). It reduced the leak slowly and by the time I did a following oil change the leak stopped.

[Darrel]

its a bit of a long shot, but the only other things on that side of the engine (started side...) that i can think of would be where the oil dipstick is pressed into the block, the distributer, and the oil filter. also, i've heard that sometimes when you change the oil filter the rubber o ring sticks to the block and if you just put the new filter on with the old ring still there it leaks. just a few thoughts.

[BombThreat]

Alright thanks for the ideas. I'll take a look.

-BT

[caposto]

Mine is doing the exact same thing Bomb. Its a '91 4.0L with a 5spd and I still get oil between the engine and tranny housing. Looks like its coming from the back of the engine or maybe the tranny, however, I never lose any tranny fluil. Its definitely engine oil. I had the rear main seal replaced at the dealer a few thousand miles ago, but it leaks the same way still. I do believe its my valve cover gasket because there is built up oil gunk all around the block from the gasket down. I also get a drop of oil dangling off my oil filter no matter how hard I tighten it. I think that might be the same thing.

The Haynes says use no gasket only RTV for the valve cover gasket on a 4.0L. Is that right? Sounds like there is a gasket I can use. What's the best one and where can I get it?

Thanks.

-Chris

[theviper90210]

caposto i know this is a old thread but did you every solve your leak, i also have the same thing and a little oil dip off the oil filter like its running from the valve cover. i replaced it with a cork one but still have the leaks

[caposto]

I replaced my valve cover gasket awhile back with a factory one with the gasket built-in. I still have the same leaks. I still get oil between the engine and tranny housing and still get oil dripping off the bottom of the oil filter. I think the oil filter drip is coming from the oil filter housing. It might need to be removed and remounted with a fresh gasket. Oil could be making its way down from there to between the engine and tranny housing. Just a hunch at this point, but I've just been living with it.

Let us know if you get a resolution.

-Chris

[Mechman71]

It could be a leaky cam cap - I haven't been that deep into a 4.0 in a while, but most inline engines have a cap or plug in the block (above the flywheel) that covers the end of the cam. Sometimes this can leak. A good cleaning and coating with RTV usually stops the leak.

[mwallek]

Hi, I also had the same leak and changed that rear main oil seal 3 times before it stopped. When I changed it the first time I also changed the freeze plug/core plug that is on the end of the Camshaft. It still leaked and a further 2 attempts after changing that 2 part seal, I finally got it. The final time I installed the seal, I took a lot more time in cleaning the whole area and used a high quality RTV sealant on it as i slid it into place. I also replaced the sump Gasket with the new Rubber ones I got from 4WD. Hope this helps!

[Desertbobr]

I had oil leaking out of my distributor. It followed the case until it leaked off of my oil filter/starter/oil pan. Thought it was a main seal. I cleaned the case really well and used a flashlight and saw the oil leaking around the base of the distributor. The Distributor Gasket was $2 and fixed the problem.