Broken oil pan bolt removal

[casadejohnson]

I removed my oil pan today for paint and a new gasket. When I took it off one of the bolts broke off below the bolt head. The bolt was an odd ball one, the rest were the original bolts but this one was a replacement ( stainless I think). I tried to get it out with a "screw out" bit without any luck. I also tried drilling it, I'm guessing I'll have to heli coil it but wanted to see if there are any suggestions before I do that. The bolt is broken off two threads down so I can't get ahold of it with a vice grip or anything like that. Any suggestions? The good news is that the engine is out and on a stand so I can flip it over to work on it.

 

[Wyflyer]

drill a tiny pilot hole directly down the bolt center. Drill till it goes through the bolt or you start seeing cast iron drill cuttings.
Then increase to a larger bits till you cut out everthying but the threads. Use a pick and peel the thin sleeve of remaining thread material out of the hole. chase with a tap.

 

[gearida]

Once you have a hole drilled through the center you could also try to use a left cut drill bit, sometimes it will grab a hold of the remaining stud of the broken bolt and pull it out.