[s-cars] Help!! Evil drain plug will NOT come out

[Noah]

Two words:
Air Chisel.

With all the soaking you've done already, I'd guess that the air chisel 
would make short work of it. If you have air, and you don't have an air 
chisel, you can get one for less than $20 at wal-mart.

You would apply the chisel tip to the shoulder/built in washer on the bolt 
head. I did most of the stuff that you said that you did, and once I finally 
decided to stop beating my head on it, I took it to my mechanic friend and 
he had it off in 3 seconds with the good old air chisel.

Another thing you can try that was good for me on another occasion is the 
pipe wrench. A pipe wrench has a lot of leverage, and just bites in harder 
when you start hitting it with a hammer. Since I had this happen to me the 
first time I've always kept both a shorty pipe wrench and a 12" 5lb hammer 
in my tool bag. I'm not a big guy, but put a 5lb hammer in my hand....

Hth,
-Noah