not much heat in the F250

[jwholgate]

i have a '71 F250 with factory A/C in which i recently installed a new radiator.
also put in a 195 thermostat, new heater control valve for the missing one,
new temp sending unit, but still not getting much heat after engine warmup.
even went old school with the cardboard strapped onto the grille (Minnesota winters, dontcha know)

i/ve been replacing broken or missing Bowden cables for the heater a/c controls, so i have the glove box liner
out for access, and moved the a/c-heat door to the proper position by hand to make sure it was in the right place.

then i flushed the heater core from under the hood as best i could. seems to be decent flow both directions,
but can a heater core be plugged as far as heating capabilities go and still allow flow through?
i'm looking at a pretty invasive task if i tackle a core replacement (i have to isolate the compressor &decharge the freon, right?),
just want to have it be worth the time.

as always, look forward to hearing your thoughts.

jw holgate 71 F250 360cid AT PS PB AC 2WD

[goody]

Hi JW, That heater core is not available. I just went thru that when I needed one for my 70 with Factory Air. LMC had one listed in their catalog and I bought it but had to return it because it was too big to fit. Original cores are 6 X 6 X 2. What I did was buy an original core for a non air truck and had a local radiator shop switch the one end where the hoses go. I have always had the same problem with slow heat thru the heater, must be common on A/C trucks. I have seen it discussed in this forum before.
Don.

[jwholgate]

well, of COURSE it isn't available!

O'Reilley's says they can get me one, we'll see how THAT goes.

i've seen a couple of NOS units on eBay, good to know about the LMC misapplication..

did you install your custom core? bit of a chore, it looks like.
and if so, did it make any difference?

[basketcase0302]

I would check with both DC and NPD on the heater core, but it doesn't sound like that may be the issue.
Have you pulled the boot off of the PS fresh air and checked to see if the ducting there is plugged with leaves yet?
How is the airflow from the fan, running at high speed?
Brutal weather, (21 here this morning) to go without heat!

[jwholgate]

i know DC is Dennis Carpenter, but i'm not sure what NPD is...

i have not investigated possible blockage of the fresh air intake, that will be next.
and yes, pretty tough to drive that thing around once it gets much colder than what it is right now...

i seem to have plenty of fan strength, and it actually works on all three speeds!

[Montana71-F100]

It could very well be the heater core but before you go to the expense and trouble it may be a good idea to make sure there are no obstructions. There is an aluminum "Y" in my heater hose near the water pump that was plugged and that's what caused my heater to not put out heat.

[jwholgate]

i have that tee, too.
seemed to be a bunch of new coolant in the core when i flushed it, but i'll take
a look at those bits next time i drain the radiator down. never thought of looking there....

thanks!

[69FLATBED]

Make sure the cable is opening the in line valve all the way, mine doesnt and I have to get out and do it by hand sometimes.

[basketcase0302]

Better grab a cold, (or hot coffee this time of the year) beverage before you go here, it's a candy store for our trucks: NPD
http://www.npdlink.com/
This is not the best picture, but you can see where the flexible ducting hooks up to the fresh air vent via the fender well. You can get a small shop vac hose up in there to clean it out if that's the issue like a lot of our trucks tend to be.

[goody]

Hi JW, I am still in the process of restoring my a/c box so I have not reinstalled it yet. I put one in several years back and yes it is a big job because you have to disassemble the whole evaporator case to do it.
Don.

[jwholgate]

good times!

[flyboy2610]

Got it fixed, did ya?

[jwholgate]

no, just trying to talk it up to myself.....