I have heard stories on here and elsewhere about how Alumaseal can potentially destroy the cooling system of a vehicle. But there is another side to every story. My neighbor, who has been a heavy duty diesle mechanic for over 20 years, has been using Alumaseal in the equipment he works on and has never had a problem. So what's the verdict? Snake oil or money saver? What is your experience?

 

It can clog up the bottom of the radiator if too much is used. I use the copper version in my 96 3.8L Windstar when changing the coolant to help keep the aluminum heads sealed. It has yet to pop a gasket or have any leaks. It now has over 140,000 miles on it.
I wouldn't use it for a repair, just preventive maint.

 

I was considering using some for a pinhole leak in my radiator, but after two months, the leak seems to have fixed itself. Judging by the state of the coolant when I first got the truck last year I'm pretty sure I'll be replacing most of the cooling system soon, I just want to put it off for as long as possible. Any reason why the copper would be better than the aluminum?

 

Not sure what I used, but I put some in a leaky radiator. Not sure what brand it was. But It didn't fix it and I had to replace the radiator anyway and I found the stuff all sitting in a clump in the bottom of the radiator