StUck in open position
That depends on what the car is supposed to run at.
If the gauge is reading hot and the car is running normal temperatures, the water temperature sensor needs replaced.
This is called the Temperature light or gauge
Most likely it is coolant getting to hot and boiling over, car is most likely overheating. Check for fluid under car, and temperature gauge.
A short between the heater switch and temperature gauge.
We have no temperature gauge in our car. Didn't come equipped with one. It probably has a warning light that would illuminate if the engine was getting to hot.
Bad groung and or bad sending unit.
Possibly a leak in the coolant reservoir bottle.
you could have abad temp sensor
i have a 1999 ford escort zx2 and its running hot, changed out the thermostat thermostat cooling sensor, checked the fan and it works, the temperature gauge in side the car still showing hot, let thecar set over night and the gauge still shows hot, what else could be wrong
Thermostat is sticking.
If it is broken. It could be a faulty temperature blend door actuator.