In Reply to: Removing broken bolt on thermostat housing posted by Myron on June 19, 1999 at 00:05:57:
Spray some penetrating lubricant on the rest of the stud and let it stand for a few minutes. This might not help at all but it won't hurt anything. Then tap on the top of the stud with a hammer, not to hard (aluminum doesn't like to be beaten). This will actually free up the threads in the head. Grab on tight with a pair of VISE GRIPS and slowly try and loosen the stud. Patience is the key. You may have to keep hitting it with the hammer. If this doesn't work I have other ways of making those broken bolts/studs listen.