# Rear main seal 66 GTO



## Kentucky_GTO (Apr 26, 2008)

I have a 66 GTO, 4 Speed, Tripower 389.

Car runs well, with about 3,000 miles on the rebuilt motor.

We don't drive it often, and the rear rope seal has been leaking for a while.

I am wondering if any neoprene or improved seals are now made for these engines?

Thanks.


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## Rukee (Feb 8, 2007)

Welcome to the forums.
Yes, I do believe they make them. Also I have seen a couple of cars, including my own, which engines were removed to replace the rear main seal and the rear cam plug was actually the culprit. It leaks down the back of the motor, down the back of the oil pan and 'looks' just like a rear main leak.


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## 05GTO (Oct 6, 2004)

I've heard good things about The Viton Seal.


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## Kentucky_GTO (Apr 26, 2008)

That Viton seal looks really nice...


Anyone know of an installation writeup for it?

I'll check that cam plug as well when I pull the motor.


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## 05GTO (Oct 6, 2004)

Kentucky_GTO said:


> Anyone know of an installation writeup for it?


http://www.pontiacgroup.com/gaskets/seal_instructions.pdf


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## geeteeohguy (Feb 2, 2008)

I just installed a Viton seal in a friend's 389 about a month ago. We were doing an overhaul, and had the crank out of it. I don't think you can thread it in place with the crank in the block like you can with a rope seal.....you may deform it. It did work out very well, though. The rope seal in my '65 389 is still leak free after the rebuild I did in 1981.....I've got about 40k miles on it now. The '67 400 in my other car has leaked out of the rear main always...before and AFTER the rebuild. Next time I tear it down, you can bet I'll put a Viton (Vitron?) seal in it! Good luck
Jeff


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