[cheese country GP]

I have a '62 GP 389 that I have a dilemma with. The rear main seal is leaking a bit but not to the point I need to add oil thru the year. Leaves a spot on the floor about the size of a silver dollar after a drive or two. Cleaned it up with brake clean a few days ago & so far it's not leaked enough to drop any oil. I was going to have the seal replaced in a couple weeks but the fella that was going to do the job has informed me it's a crap shoot if it'll seal correctly & stop the leak. Apparently these engines don't seal well.

If I'm going to spend a ton of $'s I'd like to know it'll work. I'm having second thought's as to if I even want to do the repair. I'd like some of you to weigh in & see what you'd do under these circumstance's. The leak is more annoying than anything & don't like leaving a drop of oil in some one's driveway. I already have the pan gasket & seal(new style rubber, not the old rope style) so parts are not a problem. Thanks for the help.

[chiefpontiac66]

I put the new style seal in my 62, but I had the engine out of the car and apart. From what I understand, its a pretty big job to replace the seal with the engine in the car, but it may be possible. My car has been in project status for a long time so it sits a lot and I have seen a little bit of a leak now and then, but it is always a very small leak. If I were in your position, I'm not sure I would do anything just yet. Just my humble opinion.

[Ragtop Man]

The rear main seal is a rope-type. There may be an old mechanic trick to chasing out the old seal and getting a new one in, but I wouldn't want to try it. Fix may be worse than the problem.

For now, I'd get a cookie pan with some Oil Dri to catch the drip(s) Drive it as much as possible, too.

If you ever haul the engine out, you could reload with the graphite rope seal, or, convert to rear 1-pc. -- I think BOP Engineering sells the kit. Also be sure to get the good pan gasket, too.

[cheese country GP]

I should have said more in the first post. The engine was rebuilt several years ago & has maybe 8,000 miles on the rebuild. Was done in the late '90's with a rope seal. The newer style seal wasn't available at that time. Wish it had been but must live with what I have or replace it. The plan is to pull the engine & replace the seal with the newer style neoprene available today. But after talking with the mechanic I was going to have do the job, it's a 50-50 situation as to if it'll seal. Don't want to do this huge job & spend a ton of $'s & still have a leak. Torn for what to do. The car is pretty much done or as done as they'll ever be. I drive it but maybe 500 miles a year & suspect that's the problem, not enough driving & the seal has dried out too much to seal correctly. Bottom line, what to do as far as taking the engine out & replacing the seal with the neoprene style. If it doesn't seal, then I'm back to square one & haven't solved the problem, just spent a ton of $'s & still have the same problem. What to do?

[64catdroptop]

Replacing the rope type seal in the car isn't that big of a deal - been there, done that.

The issue you run into is getting the oil pan off (#1), and you're replacing a newer seal with,..... a newer seal (rope type).

Replacment rope seals....."ain't what they use to be" and are not manufactured as they were in the '60's. i.e. why your new seal is leaking, and the new rope seal you replace it with, will leak also.

Aside from pulling the engine, replacing the seal, by pulling the caps and crank, with the new rubber 2-piece.... if it were me, I'd suck up the oil puddle every now and then, and be okay with it.

Just my 2 cent's worth

-r-

[Keith Seymore]

Originally Posted by 64catdroptop

... if it were me, I'd suck up the oil puddle every now and then, and be okay with it.

Just my 2 cent's worth

-r-

x2.

But - I may not be a good data point. My previous classic was a '31 Ford Model A, which left a trail of oil behind it going down the road. They don't have a rear main seal (just a little aluminum convolution that's supposed to channel the oil back into the pan).



K

[66bonne]

Agree with those that advocate to take no action. Your mechanic is probably right in that the new seal may leak also. Wait until you need to pull the motor and then install new seal. The only Pontiac motor I've had that did not leak at least a little was because I have a vacuum pump on it to relieve crankcase pressure.

Jim

[Txbobcat]

Good advise so far. Just leave it alone.

[Deadhead]

If you replace use the Viton or however you spell it. IME that is the only one that is really sure to work when installed correctly.

Chilton has a way to do it without pulling a 389 all the way out. You pull it partially out and then stabilize and replace the seal. I have not done it, but tend to agree with others. That said, I am going to pull one to replace b/c it is annoying. As long as you don't go all crazy, you can probably do it in a couple of weekends and get everything all tidied up that makes sense when an engine is out.

[Engine-Ear]

As the baritone in the choir, singing the same song from the DarkSider Hymnal (that song being "Take it on trips and you'll reduce the drips"), start putting some real miles on it.

Seals that sit, quit.

But I have also heard that the rope seals manufactured sometime after the mid-'80s lost their asbestos content and as such lost their long term seal-ability.

Roadtrip / Seal Rescue idea: drive over to the L&M Ranch. We can grill out, have a bonfire & talk Pontiacs. We have a guest room, too.

[Andre]

My answer is a $4 drip pan. Driving will defnitely help the situation, but sooner or later the car will sit, and start dripping again.

[Blackcat]

The newer seals lack the Asbestos they used that helped the seal stand up and to last longer. Until you have your car leaving a nice amount of oil every time it sits or you loose quart or more of oil after long drives I'd just buy a floor mat that you drive your car on. You can clean the oil up easy enough. I used to save all of my old extra seals from my engine kits. Somewhere in my old storage shed is a box with them. I like and do use the old seals if I can find them.

[cheese country GP]

Ok, taken every ones advise & told the mechanic this morning I won't be letting him tear it apart. Will live with the minor leak as it is & already bought a drip pan. Oven cleaning pan, 2 for $1.99. Big investment & not sure I can afford it!!!
Thanks for all the advise.
Matt, might take you up on that invitation. Be great to see you & Mrs Matt too. Gonna take a break for a bit. Winterized the boat this afternoon & am a bit pooped. My hammock is calling!!

[Coupe62]

Just my 2 cents. I had mine replaced in my 62 Catalina without pulling the engine. It took my friend about two hours. He took out the distribitor, disconnected the motor mounts, and was able to get the motor high enough to get the pan off. And yes the new style seal works great. I have no leaks at all. Just had my engine gone through in my 62 Grand Prix and they used the new seal in that one also.]

[Engine-Ear]

Originally Posted by cheese country GP

Matt, might take you up on that invitation. Be great to see you & Mrs Matt too. Gonna take a break for a bit. Winterized the boat this afternoon & am a bit pooped. My hammock is calling!!

...these retired guys, I tell ya....

Call me when you're ready to head East, amigo.

[pfilean]

389 in my 61 was rebuilt for the PO by a shop that I have come to distrust. Oil leaks all the time and I thought it was the rear main. After a few years of oil dry on the floor I wanted to pull the engine and check out a few things and thought I would replace the main seal in the process. But to my surprise when I got it out the back side of the flywheel was dry-dry-dry. No main seal leak. But the pan gasket was not as good. So I put on a new pan gasket and now no leaks. Are you sure it is the main seal? Not that the pan gasket is easy to replace in the car either.

[cheese country GP]

Checked again on Thursday & it's really the rear seal. But(& there's always a but!!) it's just a seep & not really a leak. Had it out 3-4 times in the last week & there's NO engine oil any where. Took the inspection cover off a couple days ago & just a bit damp up inside by the seal. Guess the advise to leave it alone was the right one. Sure glad I asked. The pan is dry as can be, not leaking any place. Whew!!!!

[694.1]

I'd dump that oil whore.
Give me a jingle, perhaps I can help.