AFAIK, the only pressure regulating device in the cooling system is the
expansion tank cap.  Could it be holding too much pressure?  When my old
pickup (1953 Chevy) has similar problems, I just loosen the cap and run with
no pressure until it gets fixed.  This may not be a great idea in the
Wasserboxer, but it works great in old iron!  Check the cap.

Mike Snow

> My 1990 (180k miles) GL automatic just had it's 4th rear heater core
> burst in 12 months!
>
> It also has burst two (metal) differential coolers, flooding coolant
> into and ruining my transmission.
>
> Any ideas what could be happening?
>
> My friends are urging my to give up the car (and I am tired of
> pulling up the flooded carpet)!
>
> Thanks!
> Paul