rear main seal in a 87 gn

[bundysgn]

i need to put a rear main seal in my car and have a few questions. what is the best type or brand? can you do this with just taking the oil pan down?how hard of a job is it? where the best place to get the parts? thanks

 

[TurboBuRick]

Rear main seal replacement.

 

[turbodave231]

I'm not sure I agree with everything in that article. I have done over a hundred rear main seal jobs with great results. I never use RTV on the cap parting line. Permatex makes a red anaerobic gasket eliminator that works much better. I always use the rubber side seals and the nails. I put a good squirt of RTV in the groove first and then push the seals in. Then drive the nails between the seal and the cap. Be sure to put some assembly lube on the bearing too.

 

[TurboBuRick]

I'm not sure I agree with everything in that article. I have done over a hundred rear main seal jobs with great results. I never use RTV on the cap parting line. Permatex makes a red anaerobic gasket eliminator that works much better. I always use the rubber side seals and the nails. I put a good squirt of RTV in the groove first and then push the seals in. Then drive the nails between the seal and the cap. Be sure to put some assembly lube on the bearing too.

You use the red anaerobic on the horizontal side of the cap?

 

[turbodave231]

Yes,

The Product I'm talking about is Permatex 518 Gasket Eliminator ( GM part number 1052943 Gasket Maker). I use the product between the cap and the block on the parting surfaces, not the side seal groove. Don't need a ton, just enough to fill any gaps or voids that might exist between the cap and block. The article says to use RTV in this location.

This product is commonly used for sealing transmission and transfer case halves. It eliminates the need for gaskets where the two surfaces are highly machined. Works great. Give it a try.

 

[TurboDave]

I used the Permatex 518 on mine, just the horozontal surface. It's wierd stuff, the little bit that squished out the back of the parting line never cures! That of course is the anaerobic feature. Only cures in the lack of oxygen areas.

 

[turbo nasty]

FWIW My Zimmerman shortblock came with rubber/nail side seals. Ive done both. Problem ive encountered with sealant is getting everything super clean for the rtv/sealant to adhere and cure when doing it in the car.

 

[krazy86t]

My car had a oil leak near the rear section of the oil pan, but i could not tell if it was oil pan gasket or rear main seal. i see oil drips in the transmission torque converter cover and on the fly wheel. Rear main seal area looks clean, but it is hard to see. not seeing any obvious drips from the rear main, i was contemplating just an oil pan gasket replacement

I pulled the oil pan and found little shredded bits of black rubbery stuff in the pick-up tube screen. Is that from the rear main seal?

 

[GNONYX]

Read twice, ask lots of questions, and most the important word is PATIENCE. The board members has help me, and this site has also help me out a lot; and when in doubt ask questions.
http://www.gnttype.org/techarea/engine/rearmain.html
The Following # notation I personally did differently.
#1- Our GN don't need to raise the engine, but I did replaced the oil pickup since the screen had something embedded in the screen. After replacing the nylon camshaft gear I found the missing nylon gear tooth.
#3 I took extra precaution when removing and placing the main bearing cap inside a zip-lock bag and place it a small box, didn't want to scratch it.
#6 Don't forget to read the "NOTE"
#7 I put a thin coat of Permatex Anaerobic on the cap-to-block mating surface of the main cap and on the chamfered edge instead of the RTV sealer. I don't have where I read that Anaerobic is OEM specified, but thats why I used it. Others may disagreed, while and others may have used RTV sealer.
Most important of all, once RTV seal is in place, let it cure until the next day.
#10 Prime the engine instead of cranking it dry.
If I miss anything I know other members will chime in