Ivan Vegvary wrote:
First time ever I had my oil changed by others, they bungled the drain plug.
2000 Chevy Silverado. It was out of town and too far away to consider
redress.

The plug is either 14mm or 9/16 inch hex head. The head seems to have a
slight taper to it. The rest of the plug is an approximate 1.5 inch
shoulder probably with a gasket. I already tried moving it by chiseling
near the edge.

I suppose my best approach at this time would be to weld on a large nut that
will fit over the hex head. I'll be using wire feed welder. Other than
disconnecting the car battery, is there any other advise before I weld?
This will be my first ever overhead weld.
Drain the oil first. Oh, that might be hard. Somebody had a
bit on the net about working on a Delorean or something, and
they dented the oil pan. So, they welded a nut on the pan to
pull it out, but that caused an oil/gas vapor explosion inside
the crankcase and blew off both rocker arm covers! So, heating
the outside of the pan might not be such a good idea. No way
could you weld it with gallons of water inside the pan, I don't
know about oil, but I suspect it will be very hard to get it hot
enough to weld without boiling a huge amount of oil on the inside.

Jon