1950s 59 heater core

[60eldo]

 Just wondering how this thing works and correct me if Im rong. So you start your car and when the water gets hot , it opens the valve to let hot water into the core and now you have heat. Whats the valve there for? If no valve the water when it gets hot wood just flow threw the core and you wood have heat. Why is it there.

[Eldovert]

The valve regulates how much hot water is getting through to the core.
Cheers,Pat MacPhail

[V63]

I think the confusion is that newer cars the heater core is HOT all the time the engine is running at temperature because the HVAC uses it to blend to desired temperatures selected by its passengers.

But in older cars the heater core was only HOT when the driver desired heat and the only real regulation was by fan speed.

As a side comment, I have become aware that modern HVAC AC portion can be greatly improved by NOT allowing the heater side to be hot during excessive hot weather. I will put a manual valve to simply stop the HOT water into the HVAC during our excessive summer (7) months 🥵

[Gabe Davis]

As per the service manual, the coolant goes from the water pump to the control valve, through the core and back to the pump.





The valve stops the flow of the water through the core so it is not a continuous loop when not in use:



Both of the Defroster and Heater controls can change how much the valve is open:





I had to have the valve in my core serviced about 10 years ago. It bolts onto the core with a rubber gasket between. The gasket had deteriorated and was leaking into the footwell so I had the whole valve serviced as it was all apart.



The bowden cables from the temperature control and the defroster moves the valve open and closed. It has been a long time since I have had it apart, but I think there was linkage for controlling the airflow between the defroster duct and the heat outlet ducts connected here as well.



There is a thermostatic control as part of the valve that helps regulate the temperature by changing the amount of water flow based on the air that has moved through the core.



The core mounts to a plate that mounts to the heater box.



If I had to guess, I'd assume the Heater control opens the valve at the beginning of its throw and then adjusts how much the thermostatic valve can open depending on how far the lever is moved. The Defog control can override the Heater setting and at the De-Ice position and opens the valve fully, regardless of the thermostatic valves feedback. At least that is my interpretation of what the shop manual is saying and how it behaves when using it.

[60eldo]

Great info. Im just saying was, is the valve nessesary. I had a 65 mustang long ago, no valve just water in water out. When heat wasnt needed you just side the control from hot to cold, or somewhere in between. And a door wood close eliminating hot air. No valve , no leaks, no expenive part.

[V63]

If your heater core was hot all the time I believe that would be most uncomfortable in summer months. You could add manual heater valves to shut off the water flow to the core

[Cadillac Jack 82]

If the wire is loose or not adjusted properly it may not be pulling the tab to open the valve.  Had that issue with my 66 Toro.

[Cadillac Jack 82]

Also if someone didnt flush the coolant with the cores open wide there might be an air bubble.

[The Tassie Devil(le)]

Great info. Im just saying was, is the valve nessesary. I had a 65 mustang long ago, no valve just water in water out. When heat wasnt needed you just side the control from hot to cold, or somewhere in between. And a door wood close eliminating hot air. No valve , no leaks, no expenive part.

Someone must have removed the tap before you purchased that car, as even Ford wasn't that cheap that they would not install a heater tap.

Bruce.

[60eldo]

  What Im saying is that from factory there was no tap, just 2 4in pipes coming out of the core. Water travels threw and when water heats up you have heat. To shut heat off, simply slide leaver from heat to cold, that closes a door not to let heat into cabin.

[V63]

Someone must have removed the tap before you purchased that car, as even Ford wasn't that cheap that they would not install a heater tap.

Bruce.

Apparently ford was that cheap🤣✅, I just tried to find a heater valve for a 1965 mustang 🤣

[60eldo]

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[60eldo]

They DONT have valves, they arent nessesary, and they cost 200-300 bucks, for what