Rear main! Can't it just not leak!?!

[TurboTommy]

Ok, is one seal better than another? Is there comething I can do to reinforce it? Why? Oh why, do the rear mains seem to be such a big problem on these motors!?! Well at least for me. I've just let mine leak for the past year. I had replaced it, but it only stayed fixed for six months. It only seems to leak while I'm driving...so unless someone can give me some encouraging advice...It'll probably leak forever!

Lemme know...thanks guys!

 

[Fuelie600]

I use a 2 piece seal from the GSCA. Install it w/ the seal halves offset from the cap to block mating surface. Use silicone in the side seal cavities and a VERY light smear between the cap and block. My motor has never had a leak of any kind. Care must be taken to insure all surfaces are dry and cleaned w/ acetone or laquer thinner. HTH Brian

 

[TurboDave]

Yes, Fuelie600 hit on the one MOST important point that most folks forget or can't get accomplished when changing rear main seals.

"Care must be taken to insure all surfaces are dry and cleaned "

This point cannot possibly be emphisised enough. I also used the side seals with the supplied nails, each side seal also had a thin coat of ULTRA copper (or grey) before being inserted.

It's almost impossible to get the mating surfaces perfectly clean and dry before applying any RTV, BUT IT MUST BE DONE, or you WILL have leakes.

The light smear between the cap and block is also manditory, and that surface MUST BE CLEAN AND DRY. Or the RTV WILL NOT adhere.

I've got over 40,000 miles on mine and still not a drop leaks. Lot's of high boost race runs on that too

 

[TurboGN]

Originally posted by TurboDave
Yes, Fuelie600 hit on the one MOST important point that most folks forget or can't get accomplished when changing rear main seals.

"Care must be taken to insure all surfaces are dry and cleaned "

This point cannot possibly be emphisised enough. I also used the side seals with the supplied nails, each side seal also had a thin coat of ULTRA copper (or grey) before being inserted.

It's almost impossible to get the mating surfaces perfectly clean and dry before applying any RTV, BUT IT MUST BE DONE, or you WILL have leakes.

The light smear between the cap and block is also manditory, and that surface MUST BE CLEAN AND DRY. Or the RTV WILL NOT adhere.

I've got over 40,000 miles on mine and still not a drop leaks. Lot's of high boost race runs on that too

Tom, I followed TurboDave's method a couple of weeks ago and completely eliminated my leak. I used brake cleaner and waited 12 hours before starting the car. This was my third attempt. The first leaked because no RTV was applied to the side seals. Then I learned the side seals should not be used and to fill the cavity with RTV. I thought this was great and even replaced one in a friend's car. This seemed to work so-so but oil dropped, although very little, from the flexplate cover on both cars. The leak became a small but constant annoyance. I've made several WOTs and not even a drop will form on the flex plate cover using the TD method. I used dental floss in a few holes to temporarily hold the gasket on the pan. While down there, you may want to replace the crossover bolts with stainless and SS flat washers. Good luck, Joel

 

[TurboTommy]

Thanks alot guys.

Hopefully I can use a lift at my brother's work. It's not a job I look forward to.

 

[FJM568]

Also don't forget to put a light smear of rtv on the seam between the oil pan rail and the rear main cap before you bolt the oil pan up...They tend to leak a little bit there if you don't...

 

[gofstbuick]

I use the same procedure as TurboDave, except, instead of using RTV, I use an anaerobic sealant. This type of sealant cures in the absense of air. I put two small dots on the block corners, about 1/4 of and inch on each side of the side seals and smear a little on the face of the maincap (keeping it away from the ends of the seal). The stuff is not cheap. $6.00 for 2/10 of an ounce, or $18.00 for 2 ounces. Of course the GM dealer only had the large tube in stock .