What happens when a heater control valve goes bad?
The heater may produce hot air, but only at certain times, such as at idle, and the hot air may come and go. A faulty heater control valve may also cause the temperature gauge to behave erratically, rapidly climbing and falling, which will make it difficult to determine the temperature of the engine.
How does a heater control valve work in a car?
In some cars, the heat is regulated by a heater control valve that controls the flow of hot engine coolant from the engine to the car’s heater core. On older vehicles, the valve is operated by a cable, while newer vehicles used a vacuum actuator controlled valve. A heater control valve can fail in several ways.
How to check the temperature of a heater control valve?
Then check the temperature of the hose on the inlet and outlet sides of the heater control valve. The inlet and outlet hoses should be the same temperature. If the inlet side is warmer than the outlet side, the valve isn’t opening or opening fully. Remove the vacuum line from the vacuum motor and check for engine vacuum.
What to do if your heater is not blowing hot air?
Pinch off the hose on the outlet side of the heater control valve (the hose closest to the firewall) and drive the vehicle at highway speeds. If the blower stops blowing hot air, you’ve found the problem.
How can I tell if my car heater is not working?
THe vent doors that change the system from heat to AC are actuated by vacuum. Check for hoses that are disconnected or damaged under the dash. WIth the engine running, you may hear a hissing sound. helpful? I have a 2000 Ford Expedition that the heat does not work.
Why do I have no coolant in my heater?
If the input to the heater core is hot, but the outlet is at best luke warm, that might mean there’s no coolant flow through the core when the engine is running and the heat is set to max for some reason. Easy enough to determine by experiment. Loosen the output hose at the fire wall.
What to do if your heater won’t turn off?
You can check the position of the shutoff valve but the insides may be broken, but if the lever doesn’t move when vacuum is applied or let off, replacement is the cure. Once, I got a heater to work by jacking the front of the truck.
Why is my hot water heater still hot after plugging in?
That certainly points to a restricted heater core. If the heater core was plugged but the coolant was able to circulate around it without exchanging any heat then the outlet hose would still be hot. There is something else going on here. As a disclaimer, I have never been a professional mechanic but mechanical systems don’t defy logic or physics.
Where is the control valve on a heater?
The heater control valve allows the flow of coolant through the heater core to be controlled and switched on and off without affecting the operation of the rest of the cooling system. It may be located on the inlet or the outlet port of the heater core and activated by a cable, electronic control, or a vacuum signal.
Is the coolant valve used in all heater systems?
It is not used in all heater systems, as some manufacturers allow coolant to flow through the heater core any time the engine is running. This type of system uses a blend door to mix cooled and heated air to achieve the desired temperature.
What is the average rating of a heater control valve?
Average rating from 129,829 customers who received a Vehicle Engine Cooling Inspection. The heater control valve is a cooling and hvac system component that is commonly found on many road going cars and trucks.
What happens if a heater control valve breaks?
One of the first symptoms of a faulty heater control valve is a heater that fails to produce warm air. If the heater control valve breaks or gets stuck, the coolant flow to the heater core may be restricted or stopped completely. Without coolant flow to the heater core, the heater will not be able to produce warm air for the cabin.
Can a car not have a heater control valve?
Not all vehicle are equipped with a heater control valve. If a valve is not used, coolant continuously flows though the heater core.
How does a cable operated heater control valve work?
A cable-operated heater control valve uses a Bowden cable to drive a flap located inside the valve. As the occupant manually moves a lever in the control panel, the cable moves a flap in the valve. The vacuum valve does the same thing with a pintle and diaphragm, except this type of valve is normally open.
What are the signs of a bad heater control valve?
Many factors can cause a bad heater control valve. Here are some of the warning signs of a bad heater control valve: Heater operates erratically, putting out more or less heat without any control changes Higher-than-normal temperature gauge readings (from loss of coolant)