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How do you test a thermostat?


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Wiki User
October 29, 2009 8:19PM

It cannot be tested 'in-place' while installed in the vehicle's cooling system. It must be removed and placed (completely covered with water) in a pan or bucket and then the heat raised on the water container. You should be able to observe the valve contained within the thermostate react to the heat and open when it reaches the operating temperature of the thermostat. HOWEVER - thermostats are so inexpensive that, by the time you go to all that labor and trouble you might just as well buy a new thermostat and replace the old one.