Is StopLeak bad for radiators?

[K_Po_Uno]

I have a slight coolant leak in the radiator. You know the kind... just enough to piss you off. I was standing in the rain, in front of my friends, adding coolant.... not cool. One of them said that I should try StopLeak.

Whaddaya think?

[niall]

its good for a quick fix but it does block the core on some of the thinner rads, which can lead to long term problems so its up to you

[DanQ]

I clogged up a radiator on an old Honda years ago with that stuff.
I wouldn't recommend it.

[bimmerd00d]

it's a last resort for a radiator to get you home. It is NOT good for the engine, and you had better pray you dont have a head gasket leak. I'd hate to see what that stuff will do to an engine.

[Gooch]

Our radiators don't have a cap. The cap is on the expansion tank and you can't add stop leak to the expansion tank. Stop leak should be added to a warm engine directly into the coolant flow. If you add to the expansion tank it will justy fall to the bottom and sit there.

[tim]

Please don't put that stuff into a BMW. It's ok for rads I guess, but definitely not ok for your block.

[632 Regal]

OK...shhhhhh dont tell anyone, I tried this stuff, the chunk powder crap for my heatercore, the specifications say it wont clog a #35 screen, whatever that is. I added cause of heatercore vapor on the windshield, it sortof helped but did not do the job as stated. I am an avid anal person when it comes to these cars and openly is AGAINST adding this crap, I did and it didnt fix it so I guess what I'm trying to say is a radiator is a LOT easier to replace than a heatercore so NO dont use that crap and pop in a new radiator and be done with the nasty deed.

[K_Po_Uno]

Very helpful, thanks....

[Karl]

I understand from the theory of relativity that objects get shorter as they approach the speed of light, but this is the first time I ever saw a picture of the phonomenon...