rear main seal leak

[Cleaner13]

ok I have an oil leak in the rear main seal
I have heard that most GNs have this problem

I brought it to my mechanic/friend and he wanted me to ask if there is some sort of package or correctional parts setup that I can buy to fix it. He guessed that since it was so common maybe GM came out with some sort of parts package to correct the problem

so my question is, is there anything out there like that, that I could buy to get rid of this oil leak?

thanks

Carl

 

[Wes]

they all leak .... (or about 98% do) so just get used to it ... if there is a fix ...i've never heard of it

 

[TurboDave]

Yes, there is a fix. A new neoprene rear main seal. NOT another rope seal. Mine hasn't leaked a drop since install back about 40,000 miles ago. These engines can be made leak free, it's not that hard at all. Just takes attention to detail, and patience.

 

[Cleaner13]

Turbo Dave

where can I get this neoprene rear main seal?

thanks

Carl

 

[TurboDave]

Many of our vendors carry it. I can't remember where I got mine. Could have been ATR, or Cotton's, or Kirban's.

 

[Wes]

i have the neoprene...it is not necessarily a fix ....it still leaks.....

 

[TurboDave]

Originally posted by Wes
i have the neoprene...it is not necessarily a fix ....it still leaks.....

Shouldn't. But as I said, takes extreme patience, an eye for detail, and RTV in the "right" places.

 

[Joe Tiano]

you can get the seal at ANY parts store...like dave said...it must be clean!..use plenty of brake parts cleaner on the cap& block...I also use kite string to tie the pan gasket to the pan ... in a few places....then get a few pan bolts started...cut the string that i used to "hold" the gasket in place! joe

 

[BoostKillsStres]

Dave,
So, what are the "right" places to put rtv? Do you also offset the seal or keep it flush w/ the block and cap as felpro recommends? I'm doing mine this week and would like a no leaker when I'm done.

 

[TurboDave]

Let's see if I can remember all my steps.

No, I don't offset them.

First and formost, and the most difficult part of the whole job.

Everything MUST be "operating room clean"!!! If there is the slightest trace of engine oil on any part that is to receive RTV, the RTV is rendered useless and might as well not be there. I can't possibley emphisize this enough.

Once the old seals are out (#4 main cap removed of course), the clean everything with some good cleaner, preferably brake cleaner because it evaporates away and doesn't leave a residue like carb, and engine cleaners do. Carb cleaner will work in a pinch but takes a LOT longer to evaporate away.

Everything spotlessly clean?

Install uppper seal.

Install lower seal in cap.

Now comes the tricky part, and the reason the parts be clean and dry.

There are two common areas that the seals leak
1. The space between the main seal its self out to the side seals, this is where the rear main cap touches the seating surface. This always seems to get neglected

2. The area at and around the side seals at the part of the main cap that touches the oil pan.

Number 1 is the usual culprit with number 2 a close second.

Here's where I differ with several folks on the proper side seal method. Many will tell you to fill the side seal void with RTV (the prefered method for the dealership). I however, strongly recommend using the provided side seals. And here's how I prep them.

I run a very very thin bead of rtv out from the main seal (cap surface) out to where it meets and touches the side seal.

I coat the side seals with RTV, not a lot, just a good coating, lay them in their chanels on the main cap. Place the main cap and bolt it in place with only a few pounds of torque (enough to seat it all the way into it's place).
Then I also use the provided "nails" and drive them into the side seals to ensure the RTV is properly spread in the channels.
Now, torque the rear cap to specs.
Trim the nails to length with cutters that will cut flush.

Let dry for a minimum of 12 hours.

You must also use a liberal daub of RTV out at the edges of the Main cap meat the block (at the side seals) to ensure that little crack doesn't leak past the pan gasket.

REMEMBER: Everything must be perfectly cleaned of oil and dry!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Otherwise your just peeing into the wind.