Why doesn't the temperature gauge of a 93 Ply Voyager 3.0 go up when driving but if parked goes up to normal?

Answer 1

I presume the engine is running when the car is parked if the temperature guage does not move to the normal position when the car is moving at road speed but goes up when the car is stopped and the engine idling, then more than likely the thermostat is bad and needs to be replaced. If you se that the temperature guage is in the normal position anafter the car has been running a while and the temperature guage then goes down when the car is moving at road speed, then this confirms that the thermosta is bad.