Sorta in a dilemma right now. I broke the head of a bolt while trying to screw it into my thermostat cover. What makes it even worse is that it broke flush with the housing and a piece of the screw extractor drill bit broke off inside the hole i tried to drill to make. Not even a piece of that bit is sticking out so i cant grab it and also I had a friend take a bigger bit to drill on top of it and it wont go anywhere.

Well now that that's out, I decided to give up on drilling. Would I need to change the water pump and housing or do I just need the housing? Or am I completely off and you have no idea what im talking about. If so please school me. I'm always willing to learn something new.

 

You could remove the waterpump with the housing still attached. Then take it to a shop with more advanced tools, the labor fees would be much cheaper. Have you seperated the housing from the water pump yet? Reason I ask is that Im trying to figure out if you are trying to tap the waterpump threads, or the housing's. A picture would help.

 

If its just for the thermostat cover, take the thermostat cover off and use some penetrating oil and a vice grip to twist the bolt back out.

 

+1 vice grips are your friend...

You could also thread two nuts on it and back the lower nut out with a wrench once removing the t-stat housing... if you dont have vice grips

 

If the screw/extractor are broken off flush with the housing, vice grips aren't going to do anything.

Those extractors are hardened steel, which unfortunately makes them more brittle.
Also since they are hardened, typically to a rockwell hardness of 58-61 like most taps, drilling them out is a big pain in the ***, since they are harderthan most of the commonly available drill bits for metal, such as high speed steel, titanium coated (the goldish ones), and cobalt penetrated. You could try buying a carbide drill bit, as that should be hard enough to drill out the extractor, but your best bet is going to be this:
If you've got access to a MIG/TIG, you can do this without removing the housing. If not, remove it and take it to a shop.
Have a nut welded to the top of the extractor/screw. TIG will by far work the best here due to a more controlled heat level, better ability to weld different alloys to each other, and zero spatter, but I have gotten away with a MIG. From there, use a ratchet to unscrew the bolt, then chase the threads with a tap, and reinstall.
Any shop will do this for a very minimal fee... especially if you mention up front that you're paying cash and don't need a receipt.

Failing that, you just need a replacement housing. The water pump itself will be fine.

 

unless its clean you wont get a strong enough bond with the weld to turn it out- also as far as drilling out ez outs/reverse drill bits- you need to use a dremel or other high speed tool like an air drill and a carbide bit.

 

+1 to welding a nut onto the broken stud. I have done it a number of times and it always worked.

 

Any broken off bolt or EZ out will have fresh, uncoated, uncorroded iron as the surface you'd be directly welding to.

 

i know what you mean. -_- happened to me also

 

Thanks for the quick replys everyone and sorry I can't take a picture of it since I don't have a camera, but the broken bolt is in the part of where you would screw in your thermostat cover.

I think I'm going to take the housing to a shop and see if they can get it out or retapped. If all else fails you can find me in the for sale section looking for a new housing.