The heater control valve (or hot water valve) opens to allow hot coolant from the engine to flow through the heater core, which heats the air supplied to the passenger compartment.
Symptoms of Wear or Failure
- Adjusting the temperature may not change the output from the heater
- Valve may leak coolant
Related Repair Advice
- When replacing the heater control valve, the shop should inspect all of the heater hoses and replace them if needed
- If the heater control valve is being replaced due to corrosion, we recommended flushing the coolant to prevent additional problems
- Heater control valves are often replaced because they leak; but if the heater hoses are being replaced, it's economical to replace the valve as well
- Not all vehicle are equipped with a heater control valve. If a valve is not used, coolant continuously flows though the heater core.