The cooling water thermostat with code 11.06011-0073.0 is a critical temperature-regulating component in the MAN L21/31 engine, responsible for maintaining the engine within its optimal operating temperature range. By automatically controlling coolant flow based on thermal conditions, the thermostat ensures rapid warm-up, stable combustion performance, and effective protection against overheating. Its precise response characteristics directly contribute to improved fuel efficiency, reduced mechanical wear, and extended service life — especially under continuous heavy-duty marine and power-generation operation.