Originally Posted by Yamahammer
The tstat housing attaches with studs/nuts. The nut snapped the stud off?
that, or he's referring to the 3 x10mm bolts that hold the thermostat cover on the housing. they do tend to snap. I haven't heard about the nut snapping the stud off. the likely hood of that happening is slim because it would most probably pull the stud out of the head with the nut first, unless it was REALLY corroded.
you could drill it out with a slightly smaller diam bit and retap it. shouldn't be a big deal. if heat didn't work you weren't using something hot enough. propane won't do it. you need a temp higher or a torch.