Overview The thermostat housing is a vital component in the cooling system of the Mercedes-Benz M271 CGI engine, which is a 4-cylinder inline petrol engine used in various Mercedes-Benz models, including the C-Class (W204), E-Class (W212), and SLK-Class. The housing integrates the thermostat valve, which regulates the engine temperature by controlling coolant flow between the engine and the radiator. Function …