rusty screw on thermostat housing snapped

[az79spider]

bottom screw that is in thermostat housing facing front of engine that the water hose "T" attaches to has snapped because of rust. How do I back this out now ? Do I need to buy a new thermostat housing now or is there a way to get her out ?

[manoa matt]

Depends on where it snapped. Take out the other screw and take the "T" off, there may be a bit sticking out that you can grab with vice grips and unscrew it out. A dremel with a cut off wheel can create a slot in the nub that you can use a flat blade screw driver to unscrew it. If it broke off flush with the aluminum, drilling it out will be difficult. Start with a small bit in the center and gradually work up until you drill out the "shaft" of the bolt the threads will then come out. If the bit wanders and goes into the aluminum you can then just drill out the housing to the next larger size, drill and tap the aluminum and use a bigger bolt.

[az79spider]

thanks, I will attempt the vise grip version first, I've got about 3 cm sticking out.

[narfire]

If your handy with a welder,take the housing off and put a nut over the broken stud and fill-er-up with weld. The nut is then attatched(usually) to the stud and the heat usually breaks the rust bond. Wrench on the nut and back it out.
Otherwise use a center punch to center the drill bit on the broken stud and drill. Heli coil might be used then as well.

[majicwrench]

HEAT .... if that snapped initially, you need to heat it good before trying vise grips. Heat and penetrating oil. If enough is sticking out, give it a smack with a hammer. Gotta loosen those frozen threads.

[manoa matt]

If using heat, heat the aluminum around the stud and try to keep the heat off the stud. Aluminum has a greater rate of thermal expansion than steel and will expand around the stud allowing it to be removed. Put it in a vice or you will burn your fingers. You can also try heating the whole area then quenching it in water, do that several times and it should free up.

[wikkid]

PB Blaster, heat, and then the vice grips.