Bonkers Posted October 26, 2006 Share Posted October 26, 2006 I have a rear main seal hemoraging oil like the Comanche Valdez. I had it replaced with a new seal, but the mechanice said the seal in it was almost new itself. I told him to replace it anyway and now my motor is bleeding worse than before. What causes this? For the life of me I cannot think of how a new seal wouldn't be able to work on a 143k motor. Link to comment Share on other sites More sharing options...
jeepthing07 Posted October 26, 2006 Share Posted October 26, 2006 What engine is it? 4.0, 2.5, 2.8? I have only replaced 1 rear main it was on a friends 258 it slowed the leak down then we noticed it was leaking out the back of the valve cover. If someone nicked the crank removeing the upper seal (if you have a 4.0) it will never seal. Link to comment Share on other sites More sharing options...
Oizarod115 Posted October 26, 2006 Share Posted October 26, 2006 ive heard say that a rear valve cover leak can drip to the same spot and appear to be a rear main leak? don't know if thats a possibility? Link to comment Share on other sites More sharing options...
500 MJ Posted October 26, 2006 Share Posted October 26, 2006 Ok, this really made me mad. I had an XJ with what I thought was the rear main leaking on it. It got worse and worse and then I finally replaced the seal. Drove it down the road and it still leaked. I got to looking and the oil was actually coming from the standoff that oil filter sits on. I guess that in MJ/XJ applications it is turned to face the hood and in Wranglers it faces down... Anyway... It was leaking bad and I ended up taking it off and getting 3 new O rings from the parts store for $1.74 and put them on and it was solved. THAT PISSED ME OFF. I couldnt beleive that after I had taken the whole bottom side of my engine apart and spent money on a new rear main and oil-pan gasket + got oil all over my stuff that all I had to do was this little 15 minute fix. OOOOOO I was Mad! :mad: So, check it out. There is only one bolt that holds it all together on mine and it was so covered in oil that it took forever to find in under the filter. Those O rings on mine were shot and cracked, and so much easier to replace than the rear main. EDIT: Also when mine leaked it ran down to the bottom tip of the bellhousing, making it look like the rear main. Link to comment Share on other sites More sharing options...
Kenosha Warrior Posted October 26, 2006 Share Posted October 26, 2006 I must be one lucky SOB be cause for 300 thousand km's on my 2.5L and she doesn't leak a drop! Probably 'cause the PO had the Jeep dealer in Springbrook, Ont do all the seals and work :) Link to comment Share on other sites More sharing options...
KYMJ Posted October 26, 2006 Share Posted October 26, 2006 ive heard say that a rear valve cover leak can drip to the same spot and appear to be a rear main leak? don't know if thats a possibility? Distinct possibility, happened on my 4x4. But my 2wd is dry as a bone back there. So, I'll be doing the rear main on it. Isn't there a double lip seal available? Or for that matter an offset one for a grooved crank shaft? Link to comment Share on other sites More sharing options...
87manche Posted October 26, 2006 Share Posted October 26, 2006 there is an offset one available. I think felpro makes it. Link to comment Share on other sites More sharing options...
Bonkers Posted October 26, 2006 Author Share Posted October 26, 2006 She's a 4.0/Ba10. When the leak first started I jacked the truck up and used three cans of foaming engine bright to scrub her back into her glory days. By that point there was oil everywhere so there was no easy trail to follow back. After the scrub down though the only oil I could find was at the base of the motor/tranny seam and a small seap on the valve cover. The repair happened the next day and 300 miles down the road my entire undercarrage is soaked again. Link to comment Share on other sites More sharing options...
87manche Posted October 26, 2006 Share Posted October 26, 2006 when you did the rear main did you inspect the crank for a groove? I'd give the offset seal a shot. Not a whole lot more you can do aside from resurfacing the crank. Link to comment Share on other sites More sharing options...
aemsee Posted October 26, 2006 Share Posted October 26, 2006 Any chance the mechanic put the seal (upper half) in backwards? I have seen it done, and it will leak like a biotch. Link to comment Share on other sites More sharing options...
Pete M Posted October 27, 2006 Share Posted October 27, 2006 My only experience with a 4.0 rear main was horrible. The first try I accidentally put a small nick in the seal when installing it. But I kept on going anyways and sure enough, it leaked worse than before. So I did it again. And once again it leaked. So I did some more research and noticed that the repair manual called for RTV in certain places around the seal. I'm not sure why I didn't notice that the first time, but I tried again with the silicone. It STILL leaked. Now I was getting pissed but figured that I didn't leave enough time for the RTV to cure. So I did it one more time, used lots of RTV (be careful, as you don't want chunks to break off and get into the engine), and waited overnight. That apparently did it for me and I haven't had any issues since. :D Well, with the rear main at least. Later on I fixed the valve cover, but I still haven't bothered with the oil filter adapter's seals. They leak pretty bad. Link to comment Share on other sites More sharing options...
pingpong Posted October 28, 2006 Share Posted October 28, 2006 My mysterious oil leak on Pong was caused by the distributor gasket leaking. Once I replaced that.. my oil leaksstopped for a lil while :oops: Link to comment Share on other sites More sharing options...
CWLONGSHOT Posted October 30, 2006 Share Posted October 30, 2006 I just did my valve cover gasket yesterday. I couldn't tell if I had a leak or not. I mean I KNOW I had a leak, I just didn't know if it was the Valve cover or not. ;) In looking at the old gasket and the way it came off it appears I did at least to an extent. Time will tell if I have eliminated my "rear main" leak or not. I have also had a hack of a time sealing the disco in the axle!! I redid that yesterday as well...for the third time!!! Ever since the 4x4 cable lock went in its been a Leakey. Leaks from the mounting flange. If there was more room I would add two bolts on the sides!! CW Link to comment Share on other sites More sharing options...
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