Postby smj999smj » Sun Jan 26, 2014 2:39 pm
If the thermostat is bad, it's either going to be stuck shut and overheat or stuck open and run too cold. The coolant gauge needle is normally centered in the gauge, so if you see the coolant gauge needle running near the cold side of the gauge, I would recommend replacing the thermostat. If the coolant is reaching normal operating temperature and the system has been thoroughly bled, I would look at the heater pump and air-mix mode door operation.