A small radiator-like heat exchanger mounted inside the HVAC housing. The heater core has an inlet and outlet that enables coolant flow through the core. A series of tubes and fins provide the surface area for heat exchange.
The heater core provides a source of heat for the interior of the vehicle. The driver, using the heater controls and blower motor, controls the exact amount of heat.
The heater core does not require regular maintenance by itself, but is cared for by regular maintenance of the cooling system. This includes coolant changes per the manufacturer's recommendations. Symptoms of a faulty heater core include coolant on the floor of the interior, a strange smell while the heat is turned on, and poor heater output. Have these symptoms checked out by a qualified technician, who can quickly determine where the fault lies. Problems with a heater core only tend to get worse; so don't put off having the system checked.