Stop leak for rear main seal? What are the forums thoughts on this stuff?


Mine weeps about half a quart every two weeks or so, roughly. Not an alarming leak, but enough of one to have to remember to stay on top of it. I would happily just replace the seal if I had the equipment to drop the transmission, but I don't. Nor do I really have the $$$ to take it into a shop to have it done.

So there's the general question, I guess. Heh. Would a $10 bottle of Bar-S be worth dumping into the engine?

 

in the 50s and 60s engines when the rear seal or the valve seals was bad, I would add a little transmission fluid to the oilit would swell the rubber and slow the leak, sometimes stop it

 

Stop leak only fix's one issue. If the seal is dry and hard stop leak will help. If there is anything else wrong with the seal it can make the leak worse. I think the only reason the stop leak stuff is still around is because of the one or two in a hundred it does help are very vocal about it and the 25% of the people it makes worse just assume it was already to far gone. IMO there only time I would try it is if the car had been sitting for years and you really had nothing to lose, meaning if it does not work your pulling the motor and resealing it anyway.

Stop leaks makes the seals soft and expand, If you have a small tear in your seal then soft and expanding is the last thing you want because the tear will likely get worse. The other side to it is not all stop leaks work as intended on every seal. Each seal company can make their seals out of what they want as long as they can reach the chemical resistance and wear resistance required by the designers. There is no one chemical that will effect all materials the same. This means the stop leak could have no effect or it could over soften the seal too much and cause a complete failure.

It is a roll of the dice.

 

I don't consider a half quart every two weeks a "weep", that's more like crying a fountain, lol. Must be leaving one heck of a pool on the ground too. Stop leak is worth a shot, what do you have to lose.