Which component is primarily responsible for circulating coolant through the engine, radiator, and heater core?

Which component is primarily responsible for circulating coolant through the engine, radiator, and heater core?

• A. Water pump
• B. Radiator cap
• C. Thermostat
• D. Radiator

Answer: (A)

The part that actually drives coolant around the whole system is the water pump. It uses an impeller driven by the engine to push coolant from the engine block into the cooling passages, move it through the radiator to shed heat, and also feed the heater core so the cabin can be heated. In short, the pump provides the flow that makes the loop possible. The radiator cap mainly controls pressure, not circulation. The radiator and heater core act as heat exchangers to transfer heat from the coolant to the air or passenger space; they don’t move the coolant themselves. The thermostat regulates when coolant is allowed to flow to the radiator based on temperature, but it doesn’t circulate coolant by itself.

The part that actually drives coolant around the whole system is the water pump. It uses an impeller driven by the engine to push coolant from the engine block into the cooling passages, move it through the radiator to shed heat, and also feed the heater core so the cabin can be heated. In short, the pump provides the flow that makes the loop possible.

The radiator cap mainly controls pressure, not circulation. The radiator and heater core act as heat exchangers to transfer heat from the coolant to the air or passenger space; they don’t move the coolant themselves. The thermostat regulates when coolant is allowed to flow to the radiator based on temperature, but it doesn’t circulate coolant by itself.