Heater blows hot in cold position

[redgum78]

On my 73 AC car the heater vents are blowing hot air all the time.
I think I have an issue with a heater box door not operating which I need to look into.
The main question I have is about the heater control valve, see picture of the valve removed.
It does adjust flow but it does not fully stop the flow in the closed position. First I thought the valve was stuffed but a friend has a brand new one that does the same. Can someone confirm if this valve should completely stop the flow or is it suppose to maintain a minimum flow for some reason?

Thanks 

[redgum78]

Still trying to find out if this style of heater valve should fully close or if it maintains a minimum flow for some reason? Can anyone confirm?

Thanks

Dan

[Pete in NH]

Hi,

As far as I know the valve should close completely and cut off all flow. In an A/C car you would not want hot water flow fighting the A/C.

The valve you have pictured is a mechanical type with a cable actuator, there were also vacuum controlled valves. One possibility is the cable is not adjusted properly and nor allowing the valve to fully close. Another possibility is after 40 years the rubber seal in the valve is shot, this could also be the case in the replacement valve if it is not of recent manufacture.

Good luck on finding the problem, the factory manual should outline the cable adjustment procedure.

[Dino]

I have a 2nd gen but had the same problem. The valve did not fully close and it should.

[redgum78]

Thanks guys.
Most heater valves on other cars I have worked on have had to close fully so I assumed the Charger would be the same.
It was just strange that my heater valve, my friends heater valve and the brand new replacement he brought all still pass about the same amount in the fully closed position. Either both of ours are no good and the new one is faulty, or Dodge did something a bit different and maintain a minimum flow for some reason?

The valve is adjusted correctly. I am suspecting it is worn out and the new one just happened to be faulty.

[Dino]

On mine I still had a small amount of flow when I installed the new seal. So I looked at the little arm the cable connects to and wondered if it was getting a little tired. I bent it a bit and hardened the metal and that did the trick. Now the cable pulls the valve stem tighter in the tube and sealed the flow completely.

[redgum78]

On mine I still had a small amount of flow when I installed the new seal. So I looked at the little arm the cable connects to and wondered if it was getting a little tired. I bent it a bit and hardened the metal and that did the trick. Now the cable pulls the valve stem tighter in the tube and sealed the flow completely.

Thanks Dino, I might give that a try.   

[Dino]

Looking at the valve pic you posted, I wonder if you can simply shorten the cable a bit to get the desired effect. Do you have that option? On 2nd gens there's a turnbuckle on the cable to adjust it.

[redgum78]

I have already adjusted the cable so it moves the lever to the end of the slot/travel. After reading your post I am thinking I might be able to space, modify or bend the bracket a little so the lever is pulling the rod a little further by the time it reaches the end of its travel. Maybe it will make up for the little bit of wear that is causing the leak rate.
I am not home right now so I wont be able to look at it until tomorrow. I will feedback how it works.

Cheers