1972 Skylark Custom. Can't get my heater to work. Blower motors works fine, just installed a new heater core, hoses, and water pump (all these failed, I didn't replace them just to get heat). Still no heat. I don't think the coolant is circulating. I will try to bypass the vacuum diaphragm in the return hose to the water pump from the heater core, but when I replaced the hoses, I checked the valve manually and it worked. What can I do to check the vacuum to the valve properly? What should it be? I can't find that info. Any help or ideas would be greatly appreciated.
I used a Mighty Vac when I worked on mine. It gives you a vacuumn source and a guage at the same time. You should be able to hold vacuumn when the controls are at cold and off. Then cycle through the system. You will loose vacuumn when a vacuumn valve is activated then it will hold vacuumn after it is reapplied. You can also use it to test each vacuumn valve. If you do not have a Mighty Vac you should get one. There are a lot of other things you can use it for.
