For some reason on my 65 there seems to be heat coming in from my heater box all of the time. At first i thought it was bad cables to my heater box not closing the doors all the way but now Im thinking I might be missing a heater control valve on the heater hoses themselves. I replaced the heater core and the heater box about to years ago but only recently started driving it so noticed the problem. Any one have any ideas

 

you might be missing one cable or disconnected. if you crawl under the dash the three cables should open 3 different flaps and doors from fully closed to fully open

 

I agree with kalli. Also, there should not be a heater control valve in the heater hoses.

 

the heater core will always have hot fluid flowing through it in 65. The doors inside the box control the flow of air either through the fins of the core or around it. The box may need new seals and foam on the doors but the core will always be warm so there will always be some amount of heat in the cabin from it.

You live in CA so you could easily bypass the core at the water pump and prob never notice that you don't have heat....unless you are in the mountains anyway

 

On my old motor, I had a vacuum operated valve in the heater hose. You can see it above and at the back of the PS valve cover.

http://www.midnightdsigns.com/Mustan...DSC00140-1.JPG

I had the vacuum line running into the car under the dash, and I could turn the vacuum on or off. This way it turned off the hot water in the summer and kept the interior cooler. Left on for the winter.

 

yeah i thought it was the heater cables but I even taped all the doors off and made sure everything was shut. It seemed to help but could still feel the heat. i have new cables but i didn't feel like going through the hassle of trying to get the control switch plate off after trying to reach those screws on the back. its a new heater box though but i wonder it its missing a seal? I do think I want to do something like james though, where did you pick it up at? Autozone?

 

yes, Autozone. Ask for a heater control valve out of a mid 80s ford truck. if that's not it, try 90s

There are both mechanical and vacuum styles