Thanks for all the input about my cooling problem.  I have not done the
resistance/voltage test, but I did buy the infra red thermometer at radio
shack ($39 on sale.  What a cool tool)

I took the van for a 5 mile drive, and in that time, the guage again read
slightly hot.  So I jumped out, and took some readings.  The crossover
coolant pipe was at 199 degrees, the top passenger side of the radiator was
at 185ish, and the best reading I got near the fan temp switch was 175. and
it had not switched on.  This is the hardest area to test, as getting a good
shot at the fins is hard.  I will sit and test more when I have a minute.

Question.  Has anybody else made a measurement like this?  What should that
coolant in the crossover pipe be at?  This seems a bit high.  If I understand
it, the thermostat should release at 188 (87C), and so the coolant temp
should not be very much above that.

I the radiator is new, and the thermostat is new, does this mean
underperforming water pump?  Or underperforming new thermostat?

Any help appreciated,
Peter