Closure device e.g. closure screw, for selectively closing and opening coolant discharging device of cooler of internal combustion engine of motor vehicle, has through-hole for accommodating sensor element sectionally arranged at device

The device (12) has a through-hole for accommodating a sensor element that is provided for sensory detection of a state variable of a coolant and is formed as a temperature sensor. The sensor element is sectionally arranged at the device extending into an interior of a heat exchanger of an internal combustion engine of a motor vehicle. The sensor element has an extension (28) sectionally projecting into the heat exchanger in an assembled position. The sensor element has a radially processed base (30) limited at its extension. An independent claim is also included for a heat exchanger comprising a heat exchanger housing.