Do any of the sealants for head gaskets work? I wouldn't use it on my car, but a coworker has an M3 with a head gasket leak--he's going to go with this stuff instead of paying $2800 for the real fix:

"Whenever there is a breach in the head gasket, a hot spot develops at the breach. The temperature of that hot spot can reach 3-4 times the that of the engine! When Thermagasket comes into contact with this superheated area, it catalyzes forming a High Temperature patch. The metallic alloy then transfer the heat away from the patch much like a heat sink in your stereo eliminating the hot spot and preserving the integrity of the patch"

 

Usually band-aid repairs are just that, band-aids.

I've never heard of any of these actually working long term.