BK N 66

i am so frustrated. i have put in the second rear main seal and the damn
thing still leaks oil?? i cannot be the only one that has a leaky rear main
seal?

anyone else out there that has had problems with the 2 piece rear masin
seal? i wish i could put a one piece rear main seal in it but i was told that
they only make a 2 piece seal for my 350 small block motor.

what am i going to have to do to stop the oil from dripping??
any and all suggestions are appreciated. thanks

1snake

Are you sure it's the rear main seal that's leaking? Is the crank in good shape? If so, are you installing it offset and using sealer on the ends. I've never had a problem with the 2 piece seals leaking.

Jim

DansYellow66

You might provide a little information on the manufacturer of the seal you have used and the technique your using to install it. Someone might be able to trouble shoot the part or process (positioning of the seal ends, sealent on the ends, direction of seal lip, etc). After replacement mine still drips an occassional drop after a drive and I've pretty much accepted that's the way it is always gonna be.

midyearvette

you may be installing it backwards...the taper goes toward the flywheel...

Lee H

Also look at any oil leaks near the back of the motor seeping between the block and the bell housing making it look like a rear main seal leak.

Westlotorn

If you are using the stock replacement 2 piece rear main seal you can upgrade to the Fel Pro Performance rear main seal. The material is better to handle more heat and RPM.
They are better but the standard seal usually works just fine. Tips above are right on.

jcapps

Do not use the normal fel pro one, make sure its the performance one quoted above. I had the same issue till I used this seal

rongold

I think what you mean is that the lip points inward towards the inside of the engine---That's the proper direction.

rongold

If your crank has a groove in it, Fel-Pro also makes an offset seal that has the sealing lip moved slightly so it seals against a good surface on the crank.

JohnZ

Did you use a sealant on the flat mating surfaces between the main cap and the block outboard of the 2-piece seal?

mrg

An 'occasional drop': After an engine rebuild, that's pretty much where I ended up too after a second go-round with replacing the rear main seal. The second rear main seal was a GM part. Supposedly, NASCAR engines used this seal. I think it's the same as the better Fel Pro rear main seal mentioned in the thread.

After dropping the oil pan, rear main cap removal, etc., I couldn't find anything wrong with the rear main crank journal surface. The second seal was installed, sealer applied in appropriate places, seal 'offset' from cap centerline, etc. . . The first rear main seal install was done the same way.

So far, so good - the second rear main seal worked out (except for the occasional drop).

Westlotorn

1Snake With that avatar how is anyone supposed to ever read what you wrote.
Very distracting. I may read it again, and again.

1snake

I changed it so it's not a distraction to you.

Jim

XLR8OR

Try converting to a 1 piece seal:

http://www.circletrack.com/enginetec...l/viewall.html

1snake

A total waste of time. The article plainly states why -
The problem with the two-piece seal is that it can sometimes allow oil to seep out. This really is only a problem when the engine is built on an assembly line; when a knowledgeable engine builder assembles the oil seal by hand with the proper precautions, an oil leak is a rarity.

Jim

JohnZ

The article is about converting a one-piece rear seal block to use the two-piece rear seal, not the other way around.

Westlotorn

I think you are helping?????????? I need to read your note again.

OMF

Have you tried this seal from Fel-Pro.... the 2918. The Summit site says it's a Viton seal, but I checked the Fel-Pro site and they say it's a Flouroelastomer seal, which is the best they make.

I put one of these in my sbc, and have had excellent results....no leaks at all.

When I installed it I cleaned everything surgically clean, degreased all surfaces with lacquer thinner, installed the seal with only a small amount of grease on the sealing edge only.....no lube anywhere else. Against most recommendations I put the seal in as GM designed it...even with the block deck, then I cleaned the ends of the seal with thinner again (using a Q-tip) and applied a very small dab of RTV to the end of the seal, and along the block / cap mating line as I posted above in post #10....don't forget to apply a little in the corners where the cap registers into the block. I've had good success using this method on several engines I've done.
I also use the one piece Fel-Pro pan gasket as well, and check the pan to ensure that the rails are straight....no dimples at the bolt holes.

The only time it didn't work is when I offset the seal like most are recommending.....leaked like a sieve.

Hope this helps.

SDVette

Holy 7-year old thread Batman!

GTOguy

Great post, but this thread is over seven years old. The OP is sure to have his seal replaced by now.