ahults

I have been trying to get the heat to work in my 78 pace car. I have tried a new thermostat and heater control valve. I can feel both coolant hoses going through the firewall and they are both hot. I am thinking it is the heater core but don't they leak when they go out? I have tried the heat settings and defrost all that comes out is cool air, the car only has 47,000 miles but has sat most of its life. anyone have any ideas?

AZDoug

If both hoses are hot, you have flow thru the core.

I would suspect some air vent isn't opening to let hot air pass over the heater core.

Doug

ahults

to get to the air vent would I have to take the whole dash apart or just the middle console?

jdp6000

No need to disassemble for now. There is a door in the heater core box. Its located directly below the glove box. I've accessed it by removing the glove box. If you look up to the left in the passenger side floor area you will see the connections from the switch going to the box. One is vaccum and the other looks like a bicycle cable. See if you can move the flap arm by hand. The problem could be in the box or at the switch. You can access the switch connections by removing the consol side panel.

SLVRSHRK

No heat? From the way the system is designed, you have to work to get that condition Most of these threads are about people getting too much heat, so be careful what you wish for.

The vacuum system which controls the vents as well as the heater control valve defaults to opening the control valve and the heater vents moving to the heat position. You should be able to detach the vacuum feed a coming off the manifold, cutting off vacuum, and getting heat. The fan will still work fine, so you should feel flow from the lower vents. Consequence of being designed in cold climate I guess.

If that doesn't illuminate a problem, I would go back and look at the heater hoses again to verify that they are getting hot simultaneously and not from radiating heat. That should verify flow.

Good Luck