Rear Main Seal Leak

[new_owner]

Hello,

I just got a 91 LS400 (108K) and the owner told me that the rear main seal needs to be taken care of...any ideas how urgent it is and how much it will cost?

thanks,

[SRK]

The rear main seal is replaced after removing the transmission. The seal is probably around $15-$30.00, and it is an easy re and re. The transmission is not though, and 5-6 hours is more than likely the flat rate to re and re it. So the job may run $500.00 depending on the shop.

Place some paper under the engine when you park it and monitor the amount and source of the leak. If it just spots a bit, you can leave it for now. Also check the PCV valve because if it is plugged, the crankcase will overpressurize and cause a leak past an otherwise good seal.

[VBdenny]

I wouldn't accept the owners diagnositics unquestioned. Pay the 75 bucks to the dealer to have it diagosed. I'm glad to learn about the PCV valve clogging, didn't know that one. Might be something else like a leaky PS that sprays back and they guy THOUGHT it was a rear main seal. I've never seen a post about a bad rear main seal failure.

[jzz30]

it happens once in a while. but if you take these motors appart and look at the seals, even after 14years and over 100k miles on it the seals look good. but maybe just a bit stiffer than the new ones.

[JPI]

I wouldn't accept the owners diagnositics unquestioned.  Pay the 75 bucks to the dealer to have it diagosed.  I'm glad to learn about the PCV valve clogging, didn't know that one.  Might be something else like a leaky PS that sprays back and they guy THOUGHT it was a rear main seal.  I've never seen a post about a bad rear main seal failure.

I will be suprise once you raise the car up. Real main seal leakage is common on older lexus. I mean the seal get old and it does fail. Like vdenny said, I would take it to the shop and let them check out.

JPI

[lexus400]

Funny, I was just logging in to post about the rear main seal on my '91 LS

with 150k. I had a major leak at 130k and had it "fixed" at a trans shop for $600.

Levines transmission in New Haven, CT - stay away !! They were horrible to deal with and now it's leaking again. I'm not even going to try and bring it back there. Anyway, will a RMS leak do any harm as long as the oil is kept at the right level ? I'm willing to let it go as long as I'm not doing any damage to the transmission (can't it leak into and mix with the tranny fluid ?) Thanks...

Bob

[JPI]

Hello Bob,

You should bring it back and tell them your problem is not fixed yet. Are you sure your valve cover gaskets ain't leak? Usually when the valve cover gaskets do leak. I would suggest the client to replace them first. Clean everything off and tell them to come back in about a month to see if the rear main seal is leaking. Let me know Bob.

JPI

[VBdenny]

Sorry to hear about the leak. Replacing rear main seals is rather tricky. Once while driving my 66 Cutlass back from Syracuse to Tulsa, the rear main seal developed a rather major leak while I was in Missouri. By the time I got to Tulsa, the clutch was slipping from the oil. I jacked it up and pulled the engine pan. I was able to push the new seal up around the crankshaft without dropping it. I also notice several warning about very carefully aligning the flanges or whatever they are called. Never leaked again, still doesn't. Now on a Lexus, it LOOKS like you can get the whole pan off. $800 bucks seems rather high to get it replaced and have it still leak. Do you think they actually replaced it? I don't trust repair people as I have seen them lie and cheat far too many times. Not all, but the few who give the industry a bad name.

I hate wasting money so I usually put stuff off. If you keep the oil level up, you probably won't hurt anything other that cover the bottom of your car with oil.

Read up on it, I have learned the hard way that knowing as much as you can about something ahead of time is a good thing. I even started secretly marking parts prior to having something else do any repair. Amazing what you learn about people.

[lexus400]

Thanks guys.. I just changed the valve cover gaskets and oil pan gasket to rule them out. Both were leaking but not that much. I can see it leaking from the RMS

pretty clearly. Right where you remove the small access cover for the flywheel.

I'll make sure the oil stays topped up and figure out how much it's leaking. Don't know if I want to bring it back to the place I had it done. Just have the feeling if I do, I'll need a new transmission soon after. Anyone done this themselves ? I have

droppped transmissions before and have a pit in my garage. It's only about 18" deep but I can do a lot w/o having the car on jackstands.