Yesterday I started replacing my = thermostat and performing a drain, flush and refill on the coolant system on Miss Blue, = my '87 GL. In removing the top to the thermostst housing (TH), 2 of the bolts = sheared off. I had to remove the lower part of the TH from the engine block in = order to drill out the sheared bolts. There is a rubber o-ring gasket between the = TH and the engine block that I will replace when I reinstall it. Should I put = any sort of sealant on this o-ring when I reinstall the TH? Any suggestions would = be appreciated. TIA.