Bill Chiu

Mine is 1998 XJ 4.0 Auto. Noted oil leak as picture shows:


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So what's the problem and appreciate any advice. Thanks!

s14unimog

Just got done fixing mine. That's the rear main seal. do a quick search on that and you'll find a couple threads on how to replace it.

here is a helpful article about it. GL, its a messy job.

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

defconOne

Hi....from what I have been thru....it could be frm different places....
Gd start is your rear main seal....
If the starter motor is covered with oil....
It could be the distributor o-ring....oil filter adapter o-ring.....or even the forward side of the oil pan gasket....
give the engine a good wash and trace it....
Find the skippers;-)

tjwalker

Fluids migrate and can be difficult to trace the source.

The top 3 causes of oil leaks on the 4.0 are the valve cover, the oil filter adapter o-rings and the rear main seal.

Before you dig into a rear main, (which it could be) be sure that the other possibilities are ruled out......

952door4x4

I'm with tjwalker on this one. I havent changed my rear main, but it is definitely the most difficult of the three. I had a pretty good sized oil leak earlier this year. I changed the valve cover gasket ($30 something dollars and right around an hour to R&R) and I also did the oil adapter "O" ring R&R (about $10 and about the same ammount of time to complete, right around an hour). It helped a lot but it didnt completely get rid of my leak. Either way, it's nice to have piece of mind that they probably wont leak for another 15 years or so after you change them, and if it happens to clear it up then theres no need for the messy and long rear main seal replacement!

MountainGoat

I deff. Agree with everyone.... I would get the jeep real hot and hit it with some engine degreaser and just spray it every where and then wash it off youll find the leak... It can also be your head gasket I know mines leakin and I have 165k on it good luck bro

Bill Chiu

Thanks for all the advices. Very helpful and will try to fix it.

defconOne

What Tj said is true...fluid does migrate...
Learned it the hard way....he he he
After I changed the rear main seal...I can still find traces of EO on my driveway..
Decided to give it a clean wash and start tracing....
My mistake....I still drive it.....the wind pushes the leaking EO to the rear....
Give it a gd wash again....this time....no driving....start and let it idle....high rpm at times..
With a good torch....managed to get the culprit....
The distributor o-ring and the oil filter adapter o-ring.....
Both leaking at the same time.....
Now I even wonder if my main rear seal is even leaking...he he he
Well.....at least I hv change it....so it will be ok this few years...he he
Good luck bro!

Bill Chiu

It was not fixed after replacing oil filter adapter o-rings first.
Then proceeded with rear main seal replacement and seems fixed now.

Mud*Love

nice i have the same problem, replacing main seal asap

thalsten

Try removing the flywheel cover, I've found if the rear main is leaking the flywheel will be oily. If it's just oil leaking on the tranny then it could be the pan gasket.