On Tue, 6 Sep 94 20:22:22 CDT Chris Getschow said:
>So to get to the point:  how does one definitively diagnose a head
>gasket problem?  Without $helling out big buck$ to a VW mechanic,
>that is...

well ... this is what vw says:

from Service Bulletins, Model Year 1987
.......................................................................
Tech News 87-N02
Issue 2, February 1987
Cold Feet, Hot Tip

A slight "internal" compression leak into the coolant system of a water-
cooled Vanagon is not always easily diagnosed.  But what your customer
tells your Service Advisor may be very helpful to pinpoint such a
problem:
*  Temperature gauge needle moves into the red
*  Very little or no heat output
*  Coolant refill tank overflows
*  Air in the coolant system
If one or a combination of these symptoms apply, be suspicious of a
compression leak between cylinder sleeve and cylinder head.  Either
the metal sealing ring (1) or the 'O' ring (2), or both may be damaged.
.......................................................................
(1) is the outer most sealing ring; next to the cylinder head.
(2) is the inner most sealing ring; next to the cylinder sleeve.