>I am currently considering buying a VW passenger bus or Westi.
>I have the impression that there might be some concerns about the
> reliability of water cooled Vanagons.  Specifically concerning the heads.

They are wonderful vehicles, but do have problems with the cooling system 
and heads, which can be prevented (or at least reduced) with proper 
maintenance.  Details can be found at the Vanagon list archives: 
http://halfdan.med.umn.edu:8853/misc/archives/vanagon.html
-Ron Salmon