I've not used it directly, but when I worked for O'Reilly, we sold the Blue Devil stop leak for head gaskets to a lot of our commercial accounts and word on the street was that it always worked. The K&W stuff with the fiber in it also seemd to work well. They also offer a money back guarantee if I remember right on the label. So they're pretty confident in it. That would be what I would try and then if I had success, I'd sell it or trade it.
