On Feb 29, 3:02 pm, "Leo Lichtman"
wrote:
"Jim Wilkins" wrote: How about putting a big tray underneath and removing

the pan? Then you
could drill out the plug.
^^^^^^^^^^^^^^^^^
If I decided to remove the pan, I would start by drilling a hole in the plug
to let out the oil. Actually, what I would do is drill a hole in the pan to
drain it, and then weld it up later. Once the pan is off, if the plug is
hard to remove, you could drill successively larger holes in it, and then
finally clean up the threads with a tap.

Many newer steel pans are made with laminated metal for sound
reduction, two very thin layers of steel with a mastic like material
in between. (AKA Quiet metal) Can be welded, but takes a very light
touch with the TIG, and can make a mess if you are not very careful.
Where I work, we dyno new engines, and often the pans must be fitted
with bungs for oil temp, supply return etc. Often we find it easier
to use a bulkhead type fitting with sealing washers or O rings to get
a seal, rather tthan welding on a fitting. If you tap an empty oil pan
with a hammer, and it sounds totally "dead", it's probably pressed out
of quiet metal. I believe the GM Duramax Diesel uses quiet metal.
Don't know about the GM gas engines.