If I use ATP AT-205 stop leak to stop a slow leak coming from the rear main seal, will it last a long time? And if it stopped working eventually, would adding more stop the leak again?

Also, I'm going to have the transmission out anyway, so how many hours would it probably take to just replace the seal at that point? And someone told me some seals were two halves that fit together as one, and others are just all one piece. Is that true? It would seem to me that a two piece seal like that would start leaking prematurely.

 

What engine? Google it and find out what the seal looks like. As far as the stop-leak in a can, it softens and swells the seal. It'll slow or stop the leak for a while, until the seal fails and then it'll leak badly.

 

5.41 in an F-250. The pics I looked up showed it as one piece. I'm going to try to avoid the stop leak then. I read that all it does is re-hydrate the rubber after it starts to dry out. But that doesn't sound completely right.

 

Just a thought, but here's my 2 cents: I used to have an SUV that drizzled oil out of the rear main bad enough to spot the back window. It was so severe it went through a quart of oil every week or so. I misdiagnosed it as blow-by due to poor ring seal (probably was a contributing factor in the leak) and added a can of Engine Restore to it and Presto! No more engine leak. It would start leaking again after about 3000 miles, at which time I would change the oil and add another can of Engine Restore. I did that for a couple more years until I got rid of it. Not sure if they still make the stuff, but it worked great, didn't hurt a thing and kept me from pulling the engine


EDIT: Here it is, same stuff I used with great success