Cracked My Thermostat Housing...Should Have Known Better [PICS Added 6/25/11]

[enildeR]

Just to put my experience in there. I had to replace the thermostat a few years ago. I was working, and I couldn't wait for the gasket. I ran to autozone to buy gasket maker (or it was called something similar) meant for quick fixes for the thermostat housing. I cleaned everything up, squeezed that stuff onto the housing and bolted it up. I haven't had a leak or anything since. This must have been around 2007.

[Geoff]

Alternately,  if everything is cleaned up real good,  and the mating surfaces are good,  the paper gasket and o-ring can be installed with no sealer.  This also ensures that the by-pass does not get clogged.  
                                                                    Geoff
      PS- no o-ring is most probably a very bad idea, and would result in doing it over again (with an o-ring)  very quickly