I broke the top mounting bolt off while replacing the thermostat on my '08 MCS. The bolt broke flush with the engine block. Everything else is tight and reinstalled.

Interested in hearing opinions on my options.

I'm going to finish it up and refill the coolant today. I'm confident the other 2 bolts will keep it tight enough at least to drive it to a mechanic.

I'm guessing the remedy is something out of my league.

I'm pretty satisfied with my local Mini dealer - Ottos in Exton, PA. Is this something they would be equipped to do? Or, should I turn to some Mini experts…both Bimmerworks and Helix are nearby.

And lastly… will they need to completely remove the thermostat to address the issue? This would disappoint… as it was the labor to replace the thermostat that I was looking to avoid.

 

I've drilled and tapped an exhaust manifold bolt without removing the manifold. It can be done, but I highly doubt that's the route most would take in this case. The way I'd go about extracting the bolt would be to weld something to the end, and turn it out. The heat created by the welding assists in the removal. You could try to drill the bolt for an extractor, but I wouldn't recommend that. Even though I've done it with success, I've seen where they break off in the hole, then the head (or whatever it is) needs to be removed for EDM. People are going to say you can't use a helicoil in a water jacket, but I've done it. Key is to use plumbers putty on the insert.

 

I dont understand how you could have broken one of those bolts unless it was bad.

The tightening torque is only something like 17 "inch pounds" or less than 2 foot pounds. heck when I did mine i had them over tight just by hand tightening them with my socket wrench.

If you broke one because of tightening them to tight then you probably cracked the new thermostat housing.

 

If you were just installing the bolt and it broke due to over torque while installing, it may not be very hard to remove now that the force has been remove (bolt head gone). If it broke when trying to remove because it was stuck in the block then it might be difficult to remove.

So if the bolt treaded in easily and just broke when tightening, it could now be pretty loose in the block. After removing the housing,you might be able to grip a little piece of the bolt with small vise-grips or needle nose pliers and just screw it out. Otherwise an easy-out should remove it easily. If really stuck in block, I would not use much force with an easy-out because the easy-out could break off in the bolt.

 

+1 on the easy out. I have used them in all kinds of tight spaces including valve cover bolts broken flush and rounded out oil cooler/heat exchanger bolts. Most shops if you take it to them have an easy out type tool or something similar just for these cases.

 

Actually... more embarassing. I was so frustrated trying to maneuver around int he tight confines that I clearly cross threaded the bolt and figure brute force would win out.

It didn't

Going to the dealer Thursday. They will remove the new thermostat, drill and remove the bolt, and look at options from there.

Lesson learned... I have better appreciation for the labor charge when its covering work inside the engine bay, and in hard to reach locations