Engine Coolant Temperature Gauge question

[David Giannandrea]

Question 1:
Should the thermostat keep the coolant temperature relatively constant? Even
at low temps and highway driving?
Answer: easier at low temps. Deviations only at extreme temps ( <15, >95

Question 2:
What is the usual position of the needle when driving? And what is the
position of the gauge when the radiator fan kicks in?
Answer: fan comes on with A/C unless REALLY cold, otherwise about 1/2 way to
next mark.

Question 3:
I think the dots for positions 1 and 7 are calibration test marks. If I
remember correctly, the Bentley shows usage of a "Special Tool" to test the
gauge. More than likely the tool is just a rheostat. Does anyone know the
resistance values at the two test positions?
Answer: not me.

Question 4:
Does anyone have a simple method of measuring the coolant temperature with
an external thermometer?
I was thinking of taping and then insulating my electronic cooking temp
gauge probe to the Upper radiator hose. With enough insulation the outside
of the hose should be at the same temperature as the coolant inside.
Shhhhhhh . .don't tell the wife!!
Answer: You need to read temp of coolant inside the engine or 'read'  the
temp sender.
 

Conclusion: Get a new thermostat. Didn't we just do this one?

David