The Genuine BMW Hex Bolt with Washer (Thermostat Housing) - 11531740317 is a high-quality bolt and washer specifically designed for use in BMW vehicles. It is used to secure the thermostat housing in place, ensuring that the engine stays at the optimal temperature for performance and efficiency. This hex bolt and washer are made from durable materials to withstand the high temperatures and pressures of the engine. It is an essential component for maintaining the proper functioning of the vehicle's cooling system.