I just purchased a 1970 442. The heater control when it is moved to the warm side makes a noise like a vacuum leak, and does let the air get warm. Any ideas on what I can do?

 

I assume you have a car with A/C. When you move the temperature lever just off of the COLD setting, the control head applies vacuum (or removes vacuum, I can never remember) from the heater control valve on the intake manifold (passenger side, at the back of the engine). You have an leak either in the control head in your dash or on the vacuum hose between the control head and the heater control valve.


The proper fix is to fix the leak. If you want to temporarily get heat working, you can apply constant vacuum (or remove vacuum --can't remember) at the heater control valve. Any manifold vacuum port could be used to apply vacuum. To remove vacuum, just remove the hose.