Any thoughts would be greatly appreciated.  While driving my 82 diesel vanagon, antifreeze started pouring out of the crankcase.  The leak is coming from one of the three sealed ports (Row of three circular depressions on drivers side of  crankcase).  My guess is that they are some kind of vents used when casting the engine.  I've not encountered this before, and hoping someone has tackled this problem in the past.

Thanks in advance,
Markus