Leaking main seal
Thread Starter
Racer
Joined: Jun 2009
Posts: 302
Likes: 2
From: Milton Delaware
Leaking main seal
I'm kind of sure it is my rear main seal that is leaking on my 350. It is a replacement Mexico crate engine for my '73. Have no idea it is. I am sure that it is not the oil pan. How hard is it for me to replace the seal. What is the procedure without removing the engine? Which seal should I replace it with? Thanks all
Le Mans Master
Joined: Aug 2010
Posts: 5,339
Likes: 546
From: Central Texas
If it is your rear main, you might try an additive available at your local auto parts store. I had a pretty good rear main leak on my 2002 Suburban. I bought a bottle of this stuff guaranteed to stop rear main seal leaks and it worked. If you are interested I'll get you the brand and name of the product. Temporary fix for an expensive problem. 
Burning Brakes
Joined: Dec 2010
Posts: 945
Likes: 10
From: Winston Salem NC
This is the procedure I used:
http://www.corvettehacks.com/article5
I let it dry a few days before I started it. I have been driving a week now and everything looks dry.
I used rtv to between the pan and gasket and between the gasket and block. I cleaned the block and pan with paint thinner prior to installation.
http://www.corvettehacks.com/article5
I let it dry a few days before I started it. I have been driving a week now and everything looks dry.
I used rtv to between the pan and gasket and between the gasket and block. I cleaned the block and pan with paint thinner prior to installation.
Le Mans Master
Joined: May 1999
Posts: 6,692
Likes: 29
From: Texas
If it is your rear main, you might try an additive available at your local auto parts store. I had a pretty good rear main leak on my 2002 Suburban. I bought a bottle of this stuff guaranteed to stop rear main seal leaks and it worked. If you are interested I'll get you the brand and name of the product. Temporary fix for an expensive problem.
http://barsproducts.com/catalog/view...al-repair-1050
Team Owner
Joined: Mar 2002
Posts: 24,160
Likes: 78
If it is your rear main, you might try an additive available at your local auto parts store. I had a pretty good rear main leak on my 2002 Suburban. I bought a bottle of this stuff guaranteed to stop rear main seal leaks and it worked. If you are interested I'll get you the brand and name of the product. Temporary fix for an expensive problem.
It's $50 tops in parts for a good Felpro 1 piece pan gasket and RMS. Figure an hour of labor if you've done it before.
But like 7T1 said, be sure it's actually your RMS that's leaking first. I've seen a lot of leaking valve covers and distributors get blamed on the RMS.
Last edited by wcsinx; Apr 26, 2012 at 12:23 PM.
Thread Starter
Racer
Joined: Jun 2009
Posts: 302
Likes: 2
From: Milton Delaware
Thanks all for the tips. Will try the additive first. I am SURE that it is not the oil pan and the valve cover. Just got done checking all that you said it might be. But no one did chime in on how to replace the main seal. Anyone?
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Burning Brakes
Joined: Jan 2012
Posts: 943
Likes: 73
Done correctly, without a lift, replacing this seal even by an experienced mechanic is going to take more than a hour. Doing it for the first time, figure on most of the morning or afternoon. All mating surfaces need to be very clean, this will take a little bit of time, don't rush it. Read more than just the one article listed, a different perspective will only add to your confidence level. Pay attention to detail regarding where the sealant needs to be applied on the mating surface of the seals. Also, this is no guarantee that this leak will stop. When you remove the rear bearing cap and inspect the journal surface of the crankshaft for wear, the surface can't have serious grooves. Also, let the car sit for awhile before dropping the pan, it's really annoying to be raining oil as you lay on your back 
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Team Owner
Joined: Mar 2002
Posts: 24,160
Likes: 78
Burning Brakes
Joined: Jan 2012
Posts: 943
Likes: 73
I've done them in under an hour several times. Granted that is a best case scenario where I'm not dealing with a pan gasket that's fused to the mating surfaces. And I use the right tools such as proper ball joint separator and an air ratchet. I've seen guys blow an entire morning beating on steering joints with pickle forks. No, that's not me.
Burning Brakes
Joined: Jan 2006
Posts: 1,019
Likes: 18
From: St. Louis MO
did you really pore that stuff in the motor and it worked? what about the rest of the oil passageways? how does it know to just seal the rear main seal and not the rest of the motor? just courious...
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
Doing the rear main seal is not as hard as people think. I was intimidated by it for a long time, and finally just decided that I was gonna take a crack at it. It was a lot easier than I thought it was going to be.
One thing I always tell people who are gonna do a rear main seal, is to give some thought to putting a new oil pump in, as long as you're in there.
Spend the money on a nice, one-piece pan gasket. It's money well spent. The time and aggravation you save will easily pay for the gasket.
Keep the shiny side up!
Scott
Melting Slicks
Joined: Apr 2001
Posts: 3,399
Likes: 278
From: Olmsted Falls, Ohio
Follow the procedure.
This is a farily easy job, messy, but not difficult.
Use the one piece gasket. If you already bought the "standard" gasket dump it in the trash and run away. This will cause more problems for the new guys that any other.
Don't be in a rush and make sure the old gasket is COMPLETELY scraped off.
Dumping in additives to stop leaks, never fixes problems, only adds new ones.
This is a farily easy job, messy, but not difficult.
Use the one piece gasket. If you already bought the "standard" gasket dump it in the trash and run away. This will cause more problems for the new guys that any other.
Don't be in a rush and make sure the old gasket is COMPLETELY scraped off.
Dumping in additives to stop leaks, never fixes problems, only adds new ones.
Le Mans Master
Joined: May 1999
Posts: 6,692
Likes: 29
From: Texas
Had a 1976 L-82, 4-sp
Joined: Mar 2011
Posts: 5,338
Likes: 1,210
From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
It may not be your rear main seal as someone suggested. Check other areas first. I thought I had a rear seal leak and took the base pan off. No oil on flywheel. Replaced base pan gasket with a Felpro one piece. No more oil dripping from rear of base pan and front of transmission. I also changed my vv cover gaskets at the same time. After 200 miles there are no signs of any leakage.
Had a 1976 L-82, 4-sp
Joined: Mar 2011
Posts: 5,338
Likes: 1,210
From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
There are some good additives out there and some not so good. For small leaks they can be effective. I had an oil leak in my floor jack. Read somewhere to put in transmission sealer additive. Did it. It doesn't leak anymore. I guess it expanded the rubber seals. Same for an engine. It won't affect anything else inside.
