Terry,

1) After warm up, the temperature gauge should run in the center.
   You have a bad thermostat or something wrong with the temperature
   measuring system (sender, instrument voltage regulator, gauge,
   etc.).

2) The Vanagon depends on forward movement or the fan to move air
   through the radiator.  If you are stopped with the engine running,
   the radiator temperature will rise until the fan thermostat turns
   the fan on.  On my Vanagon this is about 2/3 up the temperature
   gauge scale.  Newer Vanagons have a 2 speed fan, but I think that
   yours is like mine, a single speed.

Thanks for asking,

Mike  '84 GL   '60 Vespa scooter   '58 BMW Isetta microcar