The Thermostat on the 2nd Generation MINIS are integrated into the housing. If you need a new thermostat, you have to replace the entire housing.

Due to some initial design issues, the Thermostat Housing has evolved through several iterations. The Temperature Sensor is also located on the housing, and can be removed on some versions of the housing, and molded into the housing on other versions. Since the wiring harness and the type of Temperature Sensor changed thru the iterations, the replacement Thermostat Housing (which may look different than the one on the car) may require a 'Wiring Adapter' in order for proper connection to the wiring harness on the car.

Below is a quick glance Chart that shows which replacement Thermostat Housings are correct depending on the production dates, and whether or not it will require a Wiring Adapter.

http://www.minimania.com/Mini_Cooper...lication_Guide