... this was my first guess/hope. tks for confirming my perception. so, combining responses - new o ring�+ sealant = mission accomplished for the rest of my ownership ...������� =(: D)�������< warm,happy Vanagonaut with bad hair mike h.

 

________________________________
 From: Mike B <mbucchino@CHARTER.NET>
To: vanagon@GERRY.VANAGON.COM 
Sent: Thursday, November 1, 2012 12:21 PM
Subject: Re: that dreaded rear heater ...
  
Many VW components use normal round-shaped o-rings.� They start out
round in cross-section, but get compressed and flattened into the
squared groove upon assembly.� When they've been in service for many
years, they harden and take a set into this square shape, and it's only
a matter of time before they start leaking, as they no longer are the
same size or shape.� You may be able to get it to seal up again by
adding some sealant and re-assembling the parts, but it really just
needs a new o-ring.

Mike B.

On 11/1/2012 11:41 AM, JRodgers wrote:
> There is a gasket that seals the valve to the body of the heater. The
> gasket is not like an "O"ring - round in cross section, but is instead
> square in cross section. It fits nicely into a square shaped groove.