The heater core in a vehicle climate system is used to:

• A. Transfer heat from engine coolant to cabin air
• B. Condense refrigerant in high pressure
• C. Compress refrigerant gas
• D. Filter cabin air

Answer: (A)

The heater core is used to warm the cabin by using heat from the engine’s cooling system. Engine coolant absorbs heat as it circulates through the engine. It then flows through the heater core, a small radiator tucked in the dashboard, and a blower pushes cabin air across it. Heat transfers from the hot coolant to the air, which then enters the cabin, raising the interior temperature.

The other functions listed belong to different parts of the vehicle’s climate system. Condensing refrigerant at high pressure happens in the AC condenser, not in the heater core. Compressing refrigerant gas is the job of the AC compressor. Filtering cabin air is the role of the cabin air filter.