Heater Blowing out Cold Air? 1967 F-100

[fordhombre]

Wasn't exactly sure where to put this post? Engine? Interior? Ah well,here it is.

Well, over the summer, my heater worked just fine.... hot air when i wanted it, but as I live in south Texas, that wasn't very often.

Thing is, now it's winter-time and I want some hot air, there's none to be found. Blower's working and everything, it's just that the air is cold... not hot.

It's a 1967 F-100 with the 3 knobs, pulled for heat, then twisted to be turned on. The engine's a 351w with heater hoses running to the core. There's a valve on one of the hoses, but it's open...

Any help, fellas?

[ToughOldFord]

That valve would have been my first guess, but since you're sure it's open, (not just by the control, but the valve inside is actually open.), then check that you have a thermostat. Is the truck reaching normal operating temperatures? If yes and yes then the heater core is probably plugged up with rust. You can try pulling both the hoses from it and pressure flush it out with a garden hose, otherwise replace it. Good time to clean the leaves, grasshoppers, and Priuses out of the heater box too.

[fordman]

wrong or closed valve.
low on coolant
thermostat stuck open
plugged up heater core. turn down the fan speed.
i don't think the direction of flow has anything to do with it.

[fordhombre]

I'll make sure the back-end of the hose fattens up when i open that valve, to be certain that it's opening.

the coolant levels are fine.

engine was running about 170 degrees in the summer, about 140 in the winter, which is still hot enough to give heat, right? it does have a thermostat, not sure if it's sticking tough?

i'll check heater core last, as i'm betting it's the most difficult / most expensive problem, right?

[ToughOldFord]

Those temps sound okay, but a little on the cool side. Heater should work though. It costs nothing to flush out the core and even to replace it isn't too expensive,(assuming of course the '67 doesn't use some one of a kind core.), or hard.

[fordman]

i meant the coils on the core might be plugged with headliner insulation or something not letting the full force of the air through properly. but flushing the inside wouldn't hurt. you can blow them out backwars too. the core used to cost about 20.00 for a new one. i bet they arent real expensive. the hard part is putting them in a factory air heat box. that is alot of work. puttign one in a deluze heat box isnt very hard or time consuming.

[cdeal28078]

I have had the in-line valve rust closed on the inside and break. The lever moved but the inside stayed closed. I think your temps. are too low for the good of the engine though. Every thing I have heard or read recommends at least 180 to keep the junk and water burned out of the oil.
clint

[fordhombre]

the temps were just what i tried to remember off-hand. Next time I drive it, I'll pay more attention to what they are. and then look at that valve and flush the core. thanks for all the help, guys!