Markus,
    You have a freeze plug that went bad.  Cheap and easy fix, if it
went bad on its own.  It may have blown out because the head gasket
went.   This can rust out or just blow out. Clean out the block and insert
a new plug with some black laquer aviation from-a- gasket.
                                              Eric

Markus W. Wittmann wrote:

>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
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