The heater control valve is one of the many components that are responsible for warming the interior compartment. This valve controls the flow of coolant from the engine to the heater core. Most heater control valves are operated in three basic ways. A manual cable, a thermostat type system, or even engine vacuum can control them.

The heater control valve cannot be repaired, only replaced. | When the valve is replaced, a mechanic should inspect the other heater hoses, so that they can be replaced if need be. | If the heater control valve is contaminated or corroded, the coolant in the system should be flushed when the new valve is installed.

Pressure check the cooling system. | Test operation of the valve. | Replace the control valve if bad/leaking. | Fill with coolant. | Test operation of the heater.

Since the air and heating system is a closed system, a mechanic won’t be checking your heater control valve during routine inspections and services. Instead, keep an eye on your air and heating system, and schedule an inspection if you notice that anything is malfunctioning. If your heater either doesn’t work or won’t adjust, then you possibly have a malfunctioning heater control valve, and you should schedule an inspection.

If the heater control valve is leaking then you will end up with a loss of coolant, which will eventually cause the car to overheat. A properly working heater control valve ensures the proper functioning of the heating and AC system.