Help removing drain plug from head...

[KevinK]

...looking for suggestions/advice.
   I need to remove a drain plug from a BB head (the temp sender should be there). The plug has the recessed square, ...it's smaller than 3/8, ...larger than 5/16, ...my guess is 11/32. The motor just came back from the machine shop, so I want to be careful with this...
   1.) Any ideas on who carries these "drain plug sockets", (preferrably hardened) in 11/32 size?
   2.) I am concerned about heating it with the torch (which I know I need to do), ...any thoughts on how I should go about this (besides ...carefully...: )

   Thanks,
                  Kevin
 ...photo of the block. (It's not the plug you see on the front of the head (of course) but the same style on the side that I need to remove)
 

[lcmc]

I've always used a 3/8 breaker bar. Are you sure it's not the paint that is causing a 3/8 to be to big?

[RamAirDave]

Ive run into the same problem before on the side plug on a SB head, not sure if its the same size plug or not.  A 1/2" - 10mm drive reducer fit much better.

[KevinK]

I've always used a 3/8 breaker bar. Are you sure it's not the paint that is causing a 3/8 to be to big?

   I cleaned it good, ...I wish it was 3/8, but it's not. I was able to locate a SnapOn 11/32 square 'socket', ...and it fits. (The strange part is the plug in the other side head is 3/8).
   I'll be away this weekend, ...so it will have to wait until next week to see if I can get it...

[pickelnose]

This method works great.if its to tight to unscrew as it is then you have to heat.BUT heat the plug,not the head.the way this works is,heat the plug and it tries to expand from the heat but cant because the head prevents it from doing this.while the plug is hot,spray it with WD-40 and it will shrink an the lubricant will get in the threads and it will unscrew.how much heat is trial and error.normally you heat the plug untill it starts to turn red.I know you dont want to heat,but if it wont come out and you put to much pressure on it you can break the side off of it.then you break out the drill. hope this helps

[1968RallySport]

You can buy the socket you need at any Caterpillar (CAT) dealer.