Thermostat stuck open or no stat at all. Faulty temp sensor or Gauge.
You may have air trapped in the cooling system.This will cause the gauge to spike. Try this: remove the radiator cap and allow the engine to run for about 20 minutes. Add coolant as necessary. If this does not work I would replace the stat. Finally, I would check the actual cooalant with a thermometer to determine the actual temp. I hope this helps you. Mark
A faulty thermostat might cause the temp gauge on the 2000 Nissan Altima to raise to hot when the car is not overheating. A faulty thermostat can cause the gauge to move up and down and might even turn the fan on.
It's broken
because the engine in that car does not cool down
The fuel gauge, temp gauge, and starter relay are on the same fuse (instrument panel). Does the car start? if the car starts then it is the module on the back of the instrument panel. it has 3 wires ( black, blue and yellow). once changed the guages would work fine.
bodey thermistat mate
Commonly check the temp gauge on the dash.
check the coolant temp sensor
A malfunctioning thermostat will do what you describe if it is opening at at very high temperature, at some point it probably will quit opening at all.
1min or 2 i like to wait till the temp gauge starts to move or let it get to normal temp.
If you drive the car 10 miles, and it doesn't move.
Stuck open - no heat from heater, temp gauge hardly moves off of cold. Stuck closed - overheats engine, temp gauge quickly climbs to hot.