I have an 85 GL and it too rarely turns the cooling fan on.  However, 
the gauge does rise pretty far when at a prolonged idle.
 What I've wondered is whether the 
gauge measures the temp at the engine or the radiator.  I know the 
fan is switched at the radiator.

If it is at the engine, then it could be that the water pump is not 
circulating the coolant to the radiator sufficiently to cool the 
engine and thus the radiator never turns on but the engine is indeed 
running hot.  Let's face it, it is a long push from the engine to the 
front of the van.
                       
 If it is at the radiator, then I don't think there is a problem.

Does anybody know?

Greg
Gregory V. Robinson
ajax@why.net
tcdfw@aol.com (TwinCell: 2 Cellular Phones / 1 Number)
85 BMW 535i 157K  (BMW Digest)
85 VW Vanagon  135K   (Vanagon List)