Broken Bolt

[CanadianDirty30]

Hey everyone, I was working on my 91 318is the other day changing the thermostat. As I was taking off the thermostat housing i snapped one of the 3 bolts. It has snapped flush and Ive already tried drilling and tapping it using an extractor set.

The bolt is so corroded in there that when i went to go twist out the bolt with the extractor tapped in there it just lost grip and twisted the center hole bigger. The center hole is now basically just covering the threads making it impossible to get the bolt out now or to use a larger extractor size.

I have no idea what to do, if anyone has tips and suggestions let me know

[JasonC]

Weld a nut to it.

[AndrewBird]

Step up slowly in drill size until you get to the tap drill size. Then use a center punch to break what's left of the bolt inward and use a pick to get the pieces out. Then chase with a tap and you are good to go.

If you end up messing the threads up, go with a helicoil and replace the threads.

[CanadianDirty30]

Step up slowly in drill size until you get to the tap drill size. Then use a center punch to break what's left of the bolt inward and use a pick to get the pieces out. Then chase with a tap and you are good to go.

If you end up messing the threads up, go with a helicoil and replace the threads.

Yea was thinking might have to go with helicoils cause the threads are already messed, it's my only option left. Have to look up how to use helicoils tho cause I've never had to use them before haha