Which of the following correctly identifies a part that does not belong to the cooling system?

The exhaust manifold is the part that does not belong to the cooling system. It is primarily associated with the engine's exhaust system, where it collects exhaust gases from the engine cylinders and directs them to the exhaust pipe. The cooling system, on the other hand, is responsible for managing the engine's temperature and preventing overheating.

Key components of the cooling system include the thermostat, which regulates coolant flow based on temperature; the heater core, which provides heat to the cabin by using engine coolant; and the water pump, which circulates coolant throughout the engine and radiator. Each of these parts plays a crucial role in maintaining optimal engine temperature and protecting against overheating, distinguishing them clearly from the exhaust manifold's function related to exhaust gas management.