Dan said:
> >blowing out is getting combustion pressure into the cooling system 
> >and popping 'em off.  been there, done that in a rabbit diesel.
> >
> >head gaskets would be the likely culprit. sorry.
> >
then Tim said:
> thought about this too, pressure cap should blow off pressure at 15psi or 
> so, anyone verified a pressure cap malfunction. You should blow your coolant 
> into the overflow tank, along with gasses.... anyone know if this tank 
> breathes? It should!  tim s
> 
and back to Dan:
2 things:  One, the cap may very well be malfunctioning (and that 
COULD even be the ONLY problem) and not releasing either normal 
pressure or combustion leakage.

the other:  assuming the cap is working, that coolant overflow tank 
cap  has a rubber gasket in it.  i think it seals fairly tight, being 
designed for accepting just a "burp" of pressure from the cap 
overflow, not a continuous amount.  But the construction of the 
overflow certainly isn't meant for very high pressure and maybe that 
would burst before a hose would if the cap was working normally.  
Maybe it is just a bad cap.

Lets think positive and cheap...  buy a new cap first.
Start at the dealership right off when looking for a cap.  NOBODY 
(yes, i'm danming myself to be wrong) will have a cap for the new 
wasserboxers, say 85 and up.  they are only around $12. 
-dan