I would like to know if the THERMAGASKET can really fix cracked block , blown head gasket from overheating? If any of you guys have already used it, please let me know the result cause I'm thinking abouth using it but I want some info first and I would appreciate it if you could tell me how to use it .
Thank you.

I did a Google search about the product. It seems it can be used as a temporary fix for a failed gasket. I came across nothing that stated it could help with a cracked block.
I don't enodorse repairs like this because it gives a false sense of security.
Yes, it costs less than the actual repair, but if you plan on keeping the vehicle, you would be best served by doing the repair correctly, IMO.