Heat but, no heat in 77 CP Deville

devilleguy · #1 (**permalink**) 02-11-07, 03:02 PM

Hi

Heat But, no heat.

77 Deville with climate control.

So, first thought it was a stuck thermostat but, changed that with no difference. Engine heats up and when driving at speed hot air will come out of heat vents. I can adjust tempature gauge on climate control and can make it cool or hot air that comes out. The problem is that when I turn on the blower the air instantly becomes cool and stays that way. I can make the blower go to defrost and back to floor heat, and that works OK. It is just cool air when the blower is turned on (the first second is warm).

Thanks for your help in advance.

carnut · #2 (**permalink**) 02-13-07, 08:32 PM

Plugged heater core or the blend door is not fully opening. I'd bet on a plugged heater core. Once to temperature both heater hoses should be hot to the touch. If one is cooler then the core is restricting circulation.

devilleguy · #3 (**permalink**) 03-13-07, 08:18 PM

Thanks CARNUT.

It seemed that there a air operated valve on the inlet side of the heater core. It was only open a crack and would not move.

Do you think someone has a replacement?

Regards