Engine/tranny stop leak at all effective?

[SadbutTrue]

Brought this up because just about everything on my car that can leak, does leak, at least to a degree. They have stop leak for jsut about everything, and I was wondering if any of it was worthwhile. The pos engine that I got from autozone has a rear main seal leak as well as slightly leaky valve seals, and I was wondering if a bottle or two of engine stop leak might cure that (already put one in, haven't noticed a real difference yet but I'll give it some time). I also have the C4 leak that everyone gets, and was wondering if some tranny stop leak could possibly cure that eternal drip.

Any thoughts?

 

[2nd Mustang]

I tried some many years ago for a radiator. Don't expect any miracles.

I think it was Chelle that said awhile back, "That's not an oil leak, that's horsepower sweating", or something like that.

 

[Max Power]

Only the radiator stop leak works with any amount of effectiveness. Engine and tranny stop leak is snake oil in a JB can.

 

[Mach-One-Man]

I've had good luck with the "Lucas" line of products that sells at Autozone & Advance auto parts.