My first post here so Hi all. Now my problem. Heater blows just barely warm air. Thermostat is opeing and closing as it should. full of coolant. Heater hose feels hot. Temperature control is workiing as when I move it to cold can hear a door or something shut and the air goes immideiately from warm to cold. Cant find an in hose control valve and not sure how the water flow from radiator to heater core is controled on this model. Any ideas? Any help greatly appriciated.

 

you also have a control that operates the heater /defrost /vent function . thats probably the one thats not working. does your defroster make good heat and blow good? or do you not get any air at all? If so the control has probably come loose an the back of the controller or at the door itself,bob

 

I trust your engine coolant IS running hot enough??? My own problem lies in that direction. I put a Stewart "improved" water pump, and their "performance" thermostat on my F250. I think the original 'stat was a 195 degree job, and this "performance" thermostat is a 180 degree unit with three holes drilled in it. I think I'll spend this winter with cardboard over at least half of my radiator -- otherwise that 460 will never warm up.

A heater core is just a little radiator (heat exchanger). It's possible for one to be partially blocked and have poor circulation. But I'd say bob arrington has fingered the most likely culprit. Check out your air handling carefully. When it's running, engine hot and all, heater on high, does the hose to the heater feel significantly warmer than the hose from the heater? That should be an indication the heat exchanger is working well.
Good Luck. Winter is upon us.

BTW, heater cores only fail in winter. It's part of a universal law called The Natural Orneriness of Things...

 

I get correct airflow in any position def heat mix etc, the problem is that the air is not getting hot just sort of warm. Yes the heater hose is hot. Is there an in hose valve that controls the water flow thru the hose on this model if so where would I find it as its not in the engine compartment as any other trucks ive owned.

 

I haven't had my 80's Ford long enough to know for sure. I just went out and ran my '86 F250 briefly (mostly to play with an intermittent fuel delivery problem some more). I didn't see any sign of a valve, and it sure feels like the temp control on my non-AC truck is only moving an air routing damper. But in the past, some cars had a water valve on the temperature control.

Is the hose LEAVING the heater substantially cooler than the hot one supplying the heater?