Hi Larry,
Currently I am not close to an engine so that I don't have the real setup in front of my eyes ... but it sounds like being a coolant drain hole which is closed by a large (about 30 mm diameter) bolt with an allen type head.
There should be only very little coolant leak if any. If you find only dried out runners from coolant but no leaking - don't worry to much. But if it is really leaking...
Try to fabricate an allen wrench yourself using a regular bolt whose head fits into the allen bolt.
Another two nuts on the helper bolt turned against each other and you can wind/unwind the allen bolt in the crankcase.
Good luck!
Achim
(Magdeburg, Germany)