Stripped bolt

Help! I accidentally broke one of the two bolts that holds the thermostat housing on the engine, should I drill it completely out or try to extract it?

I would definitely try to extract it, drill a small hole in the center of the bolt and use and EZ-out to reverse it out, otherwise if you drill it out your problem is going to get worse, make sure to center punch before you drill the hole or your bit may drift off center, this should be a relatively easy extraction.

Thanks, yeah I tried that with a burnish type extractor, broke it off too, would not drill out because it's such hard steel and lodged into aluminum, drilled two new holes on each side of broken bolt, unfortunately one went right into coolant, JB Welded everything, no leaks, however, tepmerature fluctuates about 50 degrees.