[jake stoyer]

when i got the car the heat wasnt hooked up the guy i bought it from said he thought the heater core leaked but didnt remember so i pressure tested it with nitrogen to about 13 psi about what normal coolant pressure is and it held so i hooked up the lines and and bled it and the heat works but only when your sitting still if i start to drive it slowly fades away so i figure thermostat might be bleeding through so i replaced it and still the same thing i have herd that the cars that had factory air which mine did someone removed it had a valve that would stop the flow of hot coolant going to the heater core i do not see the valve anywhere it appears that the lines go right from the water pump and the top of the intake right to the heater core lines sticking out of the firewall is this valve located behind the dash? cause i cant find it..is it also possible my heater core might have a partial blockage....please help

 

[cardoctor]

feel the hoses going into the core when its warm, are they both warm? or the in hot and the out cold? Like you said might be restricted. My 67 has no valve, my hoses go straight to core.

 

[jake stoyer]

there both hot

 

[Royce Peterson]

The heat is not working because the air doors are not in the right position. Likely the vacuum lines to the control or to the vacuum motors are not connected properly or leaking.

 

[jake stoyer]

they seem to be all working i hooked all them up and the doors do open...with the glove box out i can watch the one that opens the return air in to the car is there another one up in the dash???

 

[doctordesoto]

i'm sure royce is on the correct path but a few weeks back we talked about origiona intake manifold elbows---i believe they extended into the coolant instead of the steam or hot air captured in the cooling system---worth a look
doctprdesoto