I really hate to say this, but don't get your hopes too high. It's only temporary.
Here is the theory behind it.I don't believe in this crap any more than most of you. I mean, how can some liquid in a bottle fill a leak and retain 200psi compression? Not very logical.
Please stop emailing me. Here is my update-------> Thermagasket worked for ONE YEAR almost to the day, then it stopped working and head gasket breached again. My car is now JUNK. I have it listed for $1,000. and am willing to part it out. I WILL NOT RESPOND TO ANYMORE EMAILS, they will only get deleted.I used it on September 23, 2010 and have driven thousands of miles already and not one time has it overheated on me. I was also skeptical, and so was my mechanic.. He actually LAUGHED at me.. Well, guess what... He just used it on a customers truck and was completely impressed. Especially after he and his employee's all laughed because I was going to use it. AWESOME PRODUCT!
And even if it only is a temporary fix, it sure has lasted quite a while, and if it happens again.. I will use the other half that I got.. BUY IT!
Email me if you have any questions. I am located in Kansas City..
My email is my username at gmail