Heater won't heat

Fastbackin1970 · Post by **Fastbackin1970** » Fri Nov 30, 2007 6:49 pm

Both of the hoses coming off the engine to the firewall are hot so I know water is circulating but I have no heat. The fan runs fine on all speeds but still no heat. The defroster doesn't work either.

Post by **FORDification** » Fri Nov 30, 2007 7:06 pm

Sounds like a plugged-up heater core. Either that, or the flapper in the heater box isn't opening up....but since they never seal really good anyway, even if it was closed there would still be enough of a gap around it to allow a little heat out, though not very much. I'll bet on the plugged core.

You can try disconnecting both of those heater hoses from the engine and stick a water hose into one of them, and see if you can flush the core out.

Fastbackin1970 · Post by **Fastbackin1970** » Fri Nov 30, 2007 7:26 pm

Thanks!

fordman · Post by **fordman** » Fri Nov 30, 2007 9:47 pm

or the heater hose valve could be stuck closed. oh i guess if both lines are hot then that would be wrong. sorry. the defroster could be disconnected from the heater ducts to the dash. are your heater tubes in place and in good condition? can you move all of the knobs for the heater or are any of them stuck?

1971ford · Post by **1971ford** » Fri Nov 30, 2007 10:02 pm

how long has the heater sat?
i took the core out of my heater/ac and flushed it with a hose and had lots and lots of big chucks of rusty mud junk and brown water. it was bad.
i would say it is the valve in the engine compartment, but if the hoses are hot after the valve, then thats not it. i say flush the core. and like fordman said, check to see if the defroster hoses are there. air would still get to the dash if there were fairly big rips just not as much.

Fastbackin1970 · Post by **Fastbackin1970** » Mon Dec 03, 2007 5:04 pm

Found the problem at lunch today. I removed the fan and there is a door that is supposed to open and close when you turn the heater or defroster on. It closes it when you move the lever it just won't open it when you turn the heat or defroster on.

I'm not sure how it is rigged to I just left the switch in the defroster position.

basketcase0302 · Post by **basketcase0302** » Mon Dec 03, 2007 5:43 pm

Fastbackin,

It closes it when you move the lever it just won't open it when you turn the heat or defroster on.

One of the very first things I had to fix on my 71! Can't stand a foggy windshield, just not safe.

Try to pull the assembly our of the dash and make sure it's not seized/stuck. I was able to work mine free with some WD-40. They are usually all over ebay if it's broken.

Jeff

fordman · Post by **fordman** » Mon Dec 03, 2007 7:26 pm

if you need a better box or some parts from a box let me know i have three of them. i could get you the door or what ever from one of these boxes.

Fastbackin1970 · Post by **Fastbackin1970** » Mon Dec 03, 2007 7:43 pm

I can manually open and close it all day. It will close as soon as I turn it to off. It just won't re-open.

Also I bought a new thermostat today. The water temp never got above 160. I bought a 192 winter thermostat I will put in tomorrow.

nadams · Post by **nadams** » Tue Dec 04, 2007 1:01 am

This is a little off topic but I thought it was better than starting a new thread.

The temperature selection switch is sticky. I am not sure that it actually does anything other than stretch the cable when I move it. Is this connected to the hose in the engine compartment? The valve is rusted and does not look like it will move. I know it is a stupid question but I figured it was better to ask than remain uninformed.

basketcase0302 · Post by **basketcase0302** » Tue Dec 04, 2007 5:44 am

nadams,

Yes, the cable you're referring to should be hooked to the valve under the hood.
Try to un-hook the cable from the valve, lubricate with blaster or wd and work it back and forth to free it up. Same thing with the dash assembly to free up a stubborn cable.
If that don't work, it's time to replace it. I believe one of the guys Sunday told me NPD or LMC has the new valves.

Jeff

fordman · Post by **fordman** » Tue Dec 04, 2007 7:29 am

Fastbackin1970 wrote:I can manually open and close it all day. It will close as soon as I turn it to off. It just won't re-open.

Also I bought a new thermostat today. The water temp never got above 160. I bought a 192 winter thermostat I will put in tomorrow.

yea if your close enough to come pickup what you need ill just give it to you. a door or a cable what ever it is.

71PA_Highboy · Post by **71PA_Highboy** » Tue Dec 04, 2007 10:01 am

If you are going to replace the heater valve, use a plastic one rather than the metal ones... I have used them both and the plastic one has FAR less issues - no corrosion, no stickyness....

JMHO,

Eric

1971ford · Post by **1971ford** » Tue Dec 04, 2007 9:05 pm

my non plastic one in the 71 would not open, until i lubed it and used a wrench, but then it just broke. My dad got a nice plastic one from the junkyard which works great.

moparmania · Post by **moparmania** » Fri Dec 14, 2007 3:26 pm

Fastbackin1970 wrote:Found the problem at lunch today. I removed the fan and there is a door that is supposed to open and close when you turn the heater or defroster on. It closes it when you move the lever it just won't open it when you turn the heat or defroster on.

I'm not sure how it is rigged to I just left the switch in the defroster position.

Where is this "door"? My heat doesn't work either and I wonder if I have the same problem.

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