Gregg,

   Buy a genuine VW thermostat. They have an uncommon(of course) , top hat
feature. I have had some bad luck with aftermarket units sticking open.
Resist buying the colder option.
The temp gauge needle should ride over the LED after five minutes.

An infrared thermometer is a handy tool here, especially with Vanagons.
;-) I got this on sale for about $19.
http://www.harborfreight.com/infrared-thermometer-93984.html

Good Luck,
Ken
http://everybus2011.com/