selavia said:
Realistically you have two options:
1. Remove the oil pan (will make a mess if there is oil in it so lay some sheet rock or plastic to prevent spillage). Drill threw the old stud. Retap the plug. Get a new Oil Plug.
2. Remove the oil pan. Buy a replacement oil pan and use that.
*NOTE: you will need a new gasket either way.
Negative,
Get a small pin punch and lightly hammer the plug counter clockwise until you get 1 or 2 threds proud, then use multigrips to turn it the rest of the way out.
If you take your time and do nut damage the outer threads or the sump itself you could be lucky. you shouldent need to take the sump off.
A sump plug does not hold big end caps in place, abit past a nip is all you need, and if you want to be more pedantic use thread tape... it doesn't hurt
Im a first year aprentice, and on my 1st day on the job i snapped a sump plug in a brand new TD volvo truck, i used this method, worked a treat!
good luck