Blown Water pump

[Martin Powlette]

Sorry about the non group related content of this message, but I need
some great minds.
About two weeks ago I replaced a water pump on a small block V8
chevy1993 the customer said he had changed one some time back but I did
not bother to ask how long ago. He shows up today and the new pump
(2weeks old) is leaking again through the same breather hole in the
pump.  When I replaced the new pump I also replaced thermostate & rad
cap all AC Delco.  He now gives me the history ..... this is the third
pump in less than 9 months.  I am lost for ideas.  Is there a GM
bulletine covering this defect or is something wrong elsewhere.

Martin