How to drill out a bolt?
 

OK guys. The time has come. I have the fuel rail and intake off my engine (3.4l). I broke a bolt on the thermostat housing and it needs to be drilled out. What are your suggestions on tools to use. I have seen a few different options, from left handed drills to easy-outs, or drilling it out completely and rethreading it, maybe even use a heli-coil. What has worked best for you guys? Just a note, the bolt is broken inside the thread hole (not flush).

I usually use Lisle Super Out's. picked them up from the parts store. They look like torx bits. The smaller size ones seem to brake too easily but the med-larger ones have always worked for me. If you have to use one from the pack that is smaller than 11/64's I don't think I would recommend them. May turn into a bigger PITA than it already is.

drilled the bolt out, didnt want to use an extractor, was told by an ex-mechanic of many years that its better to drill it out to avoid breaking off an extractor and then really being stuck. going to drill it out a little more tomorrow and use a helicoil. then hopefully get the engine back together and running by tomorrow night to see if the thing runs (keeping my fingers crossed)

Drill it, heat the **** out of it, cool it real fast. Repeat. After that a few times, try an extractor.

if you just you a drill alittle smaller then the hole you should be fine without a helicoil. You can then just punch out the rest of the peices. Ez outs work good but you need to have your drill hole perfectly strait. I have broken them in bad spots and still have managed.