Low Engine Temperature, Poor Fuel Mileage, Low Heater Temperature, possibly transmission shifting problems/and or no high gear in Automatics. Fix it!
Yes they can stick open or closed. An automobile thermostat is just as likely to stick open as it is to stick shut. Symptoms of a stuck open thermostat are slow to reach normal operating temperature and only warm air blowing from the heater. Symptoms of a stuck closed thermostat are engine over-heating and radiator boil-over.
If it is stuck closed, the engine will overheat. If it is stuck open, the engine will take a long time to reach operating temp.
If stuck closed--vehicle will overheat very rapidly and coolant will blow out of top of radiator If stuck open--vehicle will not get to normal operating temp.
Usually the car would run cool, unless the thermostat is stuck partially open.
Little or no heat from heater/defrost if t-stat is stuck open. Engine overheats if t-stat is stuck closed.
Thermostat is stuck open Thermostat is stuck open
thermostat can be stuck open
Overheating if stuck closed, no engine heat if stuck open.
Could be a stuck open thermostat.
Stuck open thermostat.
A thermostat can be stuck open or closed. If the engine runs to cool it is stuck open. If the engine is running hot it is stuck closed. If you don't have these problems you should'nt have to change it.
If the engine is overheating, the thermostat is stuck closed. If the heater is not putting out enough hot air the thermostat is stuck open. Change the thermostat as a normal part of maintenance when changing coolant.