This housing is responsible for directing the flow of coolant to various parts of the engine and ensuring that it circulates at the right temperature.

As part of the cooling system, the thermostat housing houses the thermostat itself, which opens and closes to control the flow of coolant based on the engine's temperature. When the engine is cold, the thermostat remains closed, allowing it to warm up faster. As the engine reaches its operating temperature, the thermostat opens, allowing coolant to flow through the radiator to maintain the engine's temperature within the optimal range.