Rear Main Seal to glue or not???

[Jacob Angel (40987)]

Hi Guys,

I am in a debate with my buddy as to if you are supposed to glue in a rear main seal or not.

The engine in question is a 454 block with a 6223 427 Crank. The rear main seal is a 2 piece unit. The first one my buddy put in, ended up missing, needless to say she was dripping some oil???? It did seem as if there was a blown and eaten up seal in the oil pan. So We opened her up and did it again, and I watched. Now I don't think she is leaking anymore. (I have had 2 small drops, which may old oil from the old leak....)

In talking to some buddies I am told we should have glued in the rear main seal. I talked to my mechanic about that and he said it wasn't a good idea.

Do you guys glue in your rear main seals?

Thanks,
Jacob
NCRS # 40987

[Joe Lucia (12484)]

Re: Rear Main Seal to glue or not???

Jacob------

I don't know what you mean by "glue it in". If what you're suggesting is to apply some sort of adhesive to the rear of the seal to "glue it in place", I've never heard of such a thing being done. I don't think it's necessary and it's not specified in the Chevrolet Service Manuals. I don't think that it would hurt to do it, though, as long as the amount of adhesive used was minimal.

It is VERY important that the areas adjoining the seal parting surfaces be applied sealer as shown in the Chevrolet Service Manual, as well as other engine repair manuals. This is CRITICAL. Failure to do it will ensure a leak.

The parting surfaces of new 2 piece seals are treated with a glue which will effectively seal the 2 halves together after installation of the cap.

[Bob Imhoff (46494)]

Re: Rear Main Seal to glue or not???

What type of sealer would be recommended.

[Joe Lucia (12484)]

Re: Rear Main Seal to glue or not???

Bob-----

For the areas adjoining the seal parting surfaces, I use a thin film of Permatex Ultra Copper RTV. Most other sealers like Indian Head (which I used to use for this application) or Permatex #2 will work fine, too.

For the rear of the main seal, I can't really recommend anything. I've never used anything there. However, if I were to use anything, I'd use only something like a VERY small amount of 3M Super Weatherstrip Cement.

[Joe Lucia (12484)]

Addendum

By the way, if any sealer or adhesive is used on the rear of the main seal, then one can forget about ever replacing the seal with the crankshaft in the engine. If any adhesive or sealer is used, one will never be able to get the upper half of the seal out with the crankshaft installed. So, by itself, that should give one pause regarding the use of any sealer on the back of the seal.

[Jacob Angel (40987)]

Re: Addendum

Thanks guys, this last response is the reasone my mechanic didn't want to use any sealer to hold the rear main seal in place in the first place.

We didn't use glue on the ends of the two seals.

Are you telling me that there was already glue applied to those seals ends from the seal factory, or do I first need to take it apart and add glue to the ends?

Thanks,
Jacob

[Joe Lucia (12484)]

Re: Addendum

Jacob-----

There is supposed to be an adhesive pre-applied at the manufacturing plant to the seal parting surfaces. There certainly is nothing that appears real obvious. However, I have examined the seal ends under magnification, and there does appear to have been something applied on the ends. It is not tacky, at all, to the touch, though.

Did you apply sealer to the areas of the block which adjoin the seal parting surfaces as described in the Chevrolet Service Manual?

[Michael Brown (47483)]

Re: Addendum

I would also suggest that you rotate the seal 1/4-inch so that the edges do not line up with the block/cap mating line. I have never used sealer on the seal it's self.

[Paul Latour (38817)]

Pic of GM Instructions *NM*

[Jacob Angel (40987)]

Re: Pic of GM Instructions

Wow, I just feel like I got out of ASE mechanic school!

Thanks a bunch for all of you guy's help, and for posting the pic of the instructions... they sure are helpful.

I really feel like I know all about the rear main seal now.

Best,
Jacob
NCRS # 40987

[Paul Latour (38817)]

Re: Pic of GM Instructions

Jacob,
That was for a 1979 rear main seal. Hope it translates to your need.