It is not a sensor at all. You could have a flow issue with the radiator as that has caused the car to overheat but the head gasket damage is a result of the overheating not the cause.
To check the radiator, use a temperature gun and take the temperature of the radiator at the top and bottom and see if there is about a 40% change in temperature.
Roy
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Wednesday, February 28th, 2018 AT 6:09 PM