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Discussion Starter · #1 · (Edited)
Rear Main Seal **pics added**

I started building a motor with stage 3 heads and cam to swap into my 04 Grand Prix last Friday, and finished up getting it in today. It fired right up, and ran and sounded great. After bleeding the cooling system, and checking for any leaks, I took it on the road for its first trip. I got about a block away and the oil pressure dropped off to 0. We shut it right down, and pushed it back to the house. After putting more oil in it, we started it up for a second to see where it was leaking from. It appears to have blown out the rear main seal. What kind of pressure does it take to blow out a main seal? We put in a high pressure oil kit, and at idle, it was running between 60 and 70 psi. I never got it up to WOT, so I don't know what pressure it would have had there. I'm just glad that when we put more oil in it, and started it up, everything sounded fine accept for the oil pouring out of it. At least I did not trash my brand new motor.

Any advice or thoughts would be great.

Robert

Pics of the motor





 

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Your putting this engine in a 2004 GTP?

Your do realize that your valve covers are on backwards. :D

As for a answer to your question, I cant say for sure. Maybe the seal was slightly dammaged while being installed, it wasnt pressed in evenly, or in all the way. Or the seal bore was dammaged while removing the old one. There was a lot that could happen.

You can use the GM tool to correctly install the new seal evenly:

PN# J 34686

Hope that helps.
~Farnsworth~
 

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Discussion Starter · #4 ·
Yeas, this went into my 04 Comp G. We pulled the motor out yesterday, and coe to find out that it looks like it was not comming from the main seal, but the rear engine cover. When we got it out, the top protion of the cover gasket was blown out. We replaved the cover gasket, and the main seal since we already had it. We ran it for awhile last night, and there did not look to be any leaks, but we are going to put it on the road today.

I realized the valve covers where on the wrong side, and switched them before the motor went in.
 
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