if your crank was etched another rear main seal will do nothing.....

One thing I had done early on was to clean up the engine well. The reason I got it cheap was (as it turned out) that the bolts holding the right engine mount all sheared off in the block, allowing the engine to tilt to the right and causing the oil filter to get punctured by the engine mounting bolt on that side. Oil sprayed everywhere, and the owner didn't know where to start. I cleaned it up really well to do that work.

Another thing that I forgot to mention that seemed strange to me, was that after I cleaned it up, I put the entire jeep up on jack stands so I could run it, get underneath and figure out where the oil was coming from. I ran the thing that way for probably an hour in different conditions - in gear, idle, 4WD engaged, 2000 RPM, and never got oil to come out to figure out where it was leaking.

As soon as I drove it a few miles and came back, though, there was oil dripping. Also, the oil gets blown all over down there, and makes it that much harder to figure out where it's coming from.

I thought about the crank being scratched, but I didn't see any scratches on it, and I was pretty careful not to touch it when installing the new seal. I can't be for certain though, and I'm definitely capable of dicking up the RMS install, though I don't know how I would do it any differently.

Thanks,

maybe it is the front crank seal. are you sure it comes from the rear only or is the whole motor bottom covered

try some Bars Rear Main Seal Repair you can get it at any part store see if that helps. if it is a seal it helps repair it so it might help you figure something out

well in the drive way the motor isnt under a load nor is the oil being splashed around.......best thing i can reccomend is a black light sensitive oil dye......FYI there is a few oil passage plugs and a 2" cam freeze plug on the back of the block that could be leaking oil...although i seriously dought it.

Well, I feel a little dumb tonight. It was the valve cover gasket after all. The gasket was only $5 at NAPA, so I figured I'd just give it a try. After pulling off the cover, I could see why it was leaking so bad. Whoever replaced it before hadn't got the seal in the right place in the back of the valve cover, and it left a decent size little gap for the oil. Should have tried it first, but I just didn't think that much oil could come from something that wasn't under pressure. I guess I'm a little smarter now.

Thanks for all the help! Neil

Oh, I forgot to mention that I did put in a bottle of Bars leak stuff prior to replacing the RMS. It didn't change how much the thing leaked at all (which makes sense now, assuming the stuff works.) I don't really care for that stuff at all, but I figured I'd try it to see if it helped anything.

i bet it still leeks its the oil pan gasket -bent pan

Although I am new to the forum, I would like to add some thoughts here..

Have had my 91 XJ for over ten years, bought it for $600.00 w/only 65k/miles on it..

5speed manual bare bones sport model, but I now have over 260k/miles on it and it has never failed me.

yes I have had to change water pump battery starter alternator exhaust tires brakes belts over time, but as any vehicle one must maintain it to get its maximum usefulness out of it......which leads me to the oil leaks.....



so I had this oil leak, not a lot of oil but just enough to be thoroughly annoying anytime I parked it.

took the gunk engine cleaner, cleaned the hell outta the engine compartment. saw the valve cover was leaking but not seriously (i.e. it was seeping, not really leaking out),,,so I figure it probably was time to change the valve cover gasket (about 70k/miles on it at this time)....so I change out the gasket(got the cork/rubber gasket) not a great one as I'll explain...so for the time being I now have no oil leaks at or near the top of the motor. cool ,,,,or so I thought. next day I come out from whatever useless thing I was doing and look under the jeep and sure enough there is a small dot of oil there. I said W-T-F? where is this coming from?

turns out it was the rear main seal.....the story behind this is quite gruesome..I will condense it in the name of sanity and fear.

got the rear main seal from the dealer in Ocala Fl. (was staying at my mom's winter house there as I was going through divorce etc). this is feburary, one figures its warm in florida in feburary, WRONG! it was 29 deg F, and I spent 8 hours just getting the friggin oil pan off this truck, (pain in my a$$). SO,,,,,i was EXTREMELY careful in removing the two peice rear main seal when I finally had access to it. (still friggin cold out for florida let me tell ya, no garage just a car port which was I think NASA's wind-tunnel chamber).

Ok so now I am about the put the new rear main seal in, (yes, I had new oil pan gasket too!) well, by taking my time it actually went it very smoothly and as advertised. in the mean time I had used some semi-tack permatex sealer to attach the pan gasket to the pan and let it sit in the house for several hours while I was putting the rear main seal in.. This stuck the new oil pan gasket to the pan perfectly so that when I went to put it all back together it never squirmed or jiggled while fidgeting the pan up between the tranaxle and swaybar/sterring damper. So, after I get all the oil pan bolts up in etc, I go to put the oil filter extension housing back on ( forgot to buy new gaskets, yecchh), I get her ready to start up and pull out and oil is running out everywhere !!!!
well stupid me, I forget to put the gasket back in the oil filter housing, great so now I have no car to get anywhere and the dealer is 15 miles away, so my uncle , (god bless his soul), comes by and asks me what I'm doin (my uncle was dyin from cancer and was really weak), and I explain the scene to him so he says "c'mon I'll take you down there" (auto-parts stroes don't carry oil-filter extension O-rings, believe me). Anyway so I get the new O-ring and everything goes back together fine.

I have had since that time absolutely NO oil leaks.

I do however have the constant "seeping" of the valve cover gasket no matter what type valve cover gasket I use. I make sure when I change that gasket that everything is really really clean, so I have just learned to live with it, my oil leak is non-existent and have changed to synthetic oil as I can go much longer between oil changes (12-15k).

Guys, just my two cents here on the oil leaks..
bottom line, if you got a quarter to a half -dollar size oil spot under your jeep where the eng. meets the trans. (at least on the 4.0L motors), then the rear main seal is shot and needs fixin.
If there is any other size or amount of oil under the truck then the leak is elsewhere.

Thanks for letting me be a part of the forum! Hope I can help anyone in some small way!

cpnwrench

Hello,
I too joined this forum for the EXACT reason that brought you here. My late friend and I replaced every seal on my 1990 Cherokee, starting from the valve cover all the way down to the oil pan (valve cover, head gasket, oil filter housing, camshaft port plug, rear main seal and oil pan gasket). Everything went in once except for the RMS. We replaced the RMS TWICE and it still leaked like a sieve. After the second time, I joined and posted on this forum and most advised on an improper install with the RMS. Anyway we finally went in a third time and noticed that we were installing the darned thing in backward every time. Like they say “third time is a charm.” The only other thing that is back there (aside from the VCG) that may leak is the camshaft access plug. I did not see this being mentioned and if it was then I apologize for not seeing the post. I do not know if the plug will allow that much oil to spill and in order to get at it you’ll have to drop the tranny (and why they put a freeze plug back there, I will never understand). It’s not a terribly “hard” project, especially with someone to help and with the righ tools and equipment but it is very time consuming.
My two cents is that your seal may have been installed backward and I only say this from my own personal, blundering experience with this issue (and I had an ASE mechanic helping me).
I hope this helps and that you find out what's going on… you have my empathy on this one.

Let us know what you finally find.
EB

Teach me to read... you got it! Oh well, hopefully someone will learn from my oops and maybe help someone in the future

The ONLY way to install a new pan gasket when the engine is IN the Jeep is to attach the new gasket to the BLOCK first THEN install the oilpan.

Otherwise you run the risk of dicking up the rubber that goes around the RMS on the pan. Been there.. Done that.. Leaks like a stuck pig.

Clean the block surface VERY well.

Apply a little RTV to the block surface to hold the new gasket on.

Carefully position the new pan gasket on the block and use the oilpan BOLTS to hold the new gasket on till the RTV dries (1 hour usually).

Remove the oilpan bolts.

Install the oil pan.

Done.