I am getting heat out of my heater any time the car is moving. Upon investigating, I have found that my universal cable-operated heater valve can easily be blown through in either direction when fully shut. The valve is located in the line from the intake manifold port to the heater core; it enters the lower heater core port. The upper heater core port flows to the fitting on the water pump. I believe this is the correct setup, so I believe the closed heater control valve must be flowing enough hot water to keep the core hot.

Can anyone recommend a cable-operated valve that completely stops the flow when shut?

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

The one used in the non-electronic controlled aftermarket complete AC/Heater units like Vintage Air should be fine. They list 2; one pulls and one pushes. About $20.00 in the online catalog under heater valve.


56 Vic, B'Ville 200 MPH Club Member, So Cal.

The ones they list look identical to the one I have. I may give them a call to verify that they should not pass any liquid.

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

If you’ve got the the metal chromate plate one (typically sold to replace the vacuum heater valve on an early t bird) I’ve never had one that didn’t leak. Even if they seemed ok at idle or cruise, one good wing to 4000 rpm or so and I had heat. I’ve had 3 of them, the last one from Classic Air for an a/c system. Way more heat than the a/c could cool.

I finally went to NAPA and bought a similar (but plastic) unit for an 80’s Ford truck. Shut is shut with it. Unfortunately I can’t remember the model. I don’t like plastic, but it solved the problem. Cable operated.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

I looked up NAPA auto parts and searched “Heater Valve”. They list a lot with photos: vacuum, electric and mechanical. They show a mechanical that can screw into the intake 90* and cable operated. They also show the one in question plus many plastic ones. 

56 Vic, B'Ville 200 MPH Club Member, So Cal.

So it’s a bypass style and not just off? That’s the solution, I’ll go check their site. Thanks DLR.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

So, Four Seasons model 74628 looks the part. Napa has an identical valve, part TEM 935032. Seems like this valve would work as well as the stock setup could, assuming it stops flow through the core completely.

Should this suffice, or do I need a bypass valve as mentioned to completely isolate the core to keep heat from bleeding into the passenger compartment?

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

The NAPA looks a lot like mine. I’ve got a short piece of 5/8” garden hose with the fitting to screw on the hose bib. I hooked it up to the valve and turned it on. Closed, it held the 80 psi my house had. That’s sufficient.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

I bought a Newport electric wiper conversion kit and a manual heater-control valve to eliminate the vacuum accessories. I was not pleased about the manual heater-control valve being plastic, but feel better after reading Miker's post. Additionally, I have a shut-off valve at the manifold; if the system leaks, I'll close the valve. Hopefully, the made-in-China shut-off valve won't leak. 

Miker…the electronic valve was part of my AC conversion/addition and connected to the electronic controller. I don’t know if there is anything like it mechanical. I’ll include a photo of it. 

56 Vic, B'Ville 200 MPH Club Member, So Cal.