Broken thermostat housing bolt

[kzj90nz Junior Member Find all posts View Profile Close kzj90nz]

Hi guys,

I've got a broken thermostat housing bolt - how would you go about getting it out?

Would your preference be to use a screw extractor?

Unfortunately Toyota can't order replacement bolts and I'm away from my vehicle for the next couple of weeks.

Does anyone know the size of the bolt head (10 or 12mm?) and the length of the threaded section?

[MRW82 Member Find all posts View Profile Close MRW82]

You might be able to get it with a hammer and centre punch, tap on the end of the bolt at an angle in the direction you want it to turn, with a bit of luck it will slowly unwind. Failing that use an easy out/screw extractor.
I think you'll find the bolts are M8 (with 12mm head). Not sure on length though.

[kzj90nz Junior Member Find all posts View Profile Close kzj90nz]

Great, thanks MRW82 - much appreciated!

[Hogey66 Senior Member Find all posts View Profile Close Hogey66]

If it broke due to being seized then you may have a lot of difficulty getting it out with a screw extractor. The last thing you want is a broken extractor inside the broken bolt. May be better drilling it out and retapping the thread but you have to ensure you centre the drill perfectly to drill it out to the right size

[Brett1979 Avid PP Poster! Find all posts View Profile Close Brett1979]

It's just a threaded stud shaft with a nut that screws on to keep the thermostat housing part of the water pump torqued on evenly with the rest of the "bolts" elsewhere around the water pump. It looks like the stud comes out of the engine block itself. That's what it looked like anyway when I changed my timing belt and water pump. I don't know how you're going to be able to fix this. I myself would probably just put up with the broken stud and use a bead of FIPG to help properly seal the metal pipe thermostat cover onto the thermostat housing which will now only have two nuts to hold it on. Two nuts torqued to the 20nm and FIPG would do the job of preventing coolant leaks and will hold the cover on properly.

I just don't know how you'd actually fix it with how it looked to me.
I'm keen to see how this one pans out.