The best indication of a bad thermostat is when the radiator fluid (Antifreeze) boils over from the reserve tank, not the radiator. This is caused by the thermostat not opening at its preset temperature and all the extra antifreeze is pumped directly to the reserve tank. You will also have loss of power and the vehicle will likely stop running soon after the antifreeze boils over.
If the thermostat has failed it will need replaced.
The only way, and maybe not even then, is to take it out. You might be able to guess if the thermostat housing has been taken apart by telltale signs of excess gasket sealer in the area.
Is you Geo Tracker overheating or the temperature is running almost hot then you need to change you thermostat
You should use a thermostat gasket along with the thermostat housing ring. The gasket should be replaced every time the thermostat housing is opened.
You don't repair a thermostat. Generally they need to be replaced. They generally don't cost very much...under $10.
Would need to know if car was overheating before waterpump and thermostat was replaced.
The thermostat is done it has to be replaced.......
If your engine takes a much longer time for the thermostat heat guage to reach its required level of operatiing temperature then the thermostat may be stuck in the open position which means that it will need to be replaced.
The alternator in a car may need to be replaced if some simple signs are noticed. A noise may originate from under the hood, or lights in or on the car may dim or flash.
One of the most common signs of a bad thermostat in a Subaru is the vehicle overheats. This is a sign that something is not working right with the thermostat. You may need a new one, or you may be able to repair the issue.
Don't know what kind of vehicle you have but a thermostat housing and the clutch are not connected in any way. Need more info.
The thermostat may need to be replaced.