Hot Cab Puzzler

[yellercat]

Scratching my head over this.
1970 F-100 302 C-4 had it about 4 mos now.
Interior is getting heat with the temp selector on the cool side.
Did replace the heater core and had the control cables off and back on no apparent problem. Changed some hoses and noted that the heater control valve in the hose seemed to be ok, operable; looked like it opened and closed alright on inspection. This was month ago or so.

So now, seems like there is always warm air coming from the defrost (when on that selection) , more so on the highway speeds.
Anyway, today I drained the coolant thinking that the hoses were reversed going into the heater from engine. Swapped them so that the water pump hose exit goes to the valve. Correct? That leaves the manifold exit hose going straight thru to the heater core. ( It was the opposite when the problem was noticed ) No improvement with that change, if its even right now.

Next guess it that the valve is faulty. You guys got any other ideas?
Not sure what else to check, seems like such a simple problem to diagnose. Appreciate your thoughts and ideas.
yellerc@

[sargentrs]

This diagram is for A/C but has a great view of the heater hose and valve routing.
http://www.fordification.com/tech/image ... tegral.jpg. The water flows from the water pump, through the valve, and to the heater core inlet which is the port closest to the EDIT: engine. The outlet port connects to the intake/thermostat housing. Putting the valve in the outlet line will trap hot water in your heater core and not help your situation. You need the valve in the inlet hose. Pull the valve, close it, and try to blow through it. If you can, replace it. You can always just plug the inlet hose and hook it back up again next winter.

[jzjames]

The flaps that shut off your heat and defrost vents may be leaking heat even when they are closed.
They would have some kind of pad or seal on them which has probably worn off allowing them to be leaky.

[sargentrs]

Btw, here's my rebuild thread that shows the baffles. http://www.fordification.com/forum/view ... hp?t=73960

[yellercat]

Appreciate that guys!
Need to verify that the 'valve' side hose is on the correct heater core side.
The 'flaps' on the heater box were working correctly when it was out for the core replacement. Thanks for the links, very informative.
I'll update when I get it right and confess where the problem lay.

[sargentrs]

Looking forward to hearing what you figure out.

[yellercat]

Well, its looking more like the valve.
I have, since last post, switched the hosed on the heater core so that the intake, fender side heater core tube, is going to the water pump outlet.
Still getting too much warm air out of my defrost vents, much more so when at highway speed, and that with no fan. With fan on it is, of course, much warmer. Our Southern Summers don't need ANY help with the heat. Which reminds me of an old saying down here, "it's not the heat; it's the stupidity".
May be appropo in this case !
Anyone have a known good source for our (1970 302) heater valves? I see some listed, interested in the GOOD one, whichever that may be.

For kicks -- anyone have a shot of your 302 acting normally with the heater etc of the engine with all the hoses, valve and heater outlets clearly visable??

[1970FordTK]

Quick Question, does your set up still have the plate that has water going under the carb and the lines going to it?

[390FE1972]

I got my heater valve from Dennis Carpenter, it works good, don't know if it is any better than the rest? I see Carolina Classic F100's have them as well. Here is an interesting picture of a 1971 F100 with 16,000 miles on it, shows the heater hoses.

http://www.fordification.com/images/fai ... 9489hi.jpg

Regards!

[yellercat]

Nope, don't have that plate under the 302; but I did see one on the 390 before it was rebuilt. Not much use down South in the heat, anywho.

Will give Dennis Carpenter a look. Haven't bot from them since I did the 52' some time ago, but got alot of good stuff from them then. Thanks-
Hadn't thought of Carolina Classics, but will check there also. First one I searched was all plastic, so didn't really like that. Appreciate the linky too. Came across one pic in my files that helps too.
tanks for the replies, will follow up when I get it going COOL.

[sargentrs]

Edited my post above. The inlet port is the one on the engine side, not the fender side. I traced that diagram wrong. Overlapping hoses got me confused.
Thanks for that photo 390FE1972! Sorry for any confusion or extra work yellercat!

[yellercat]

Ha ! Wondered about that !!
Found this photo in my saved file. Not sure of the owner but credit to him/her. It shows the hoses clearly and makes it easier than readin'.
Well , guess I have lost the ability to post photos.

[m9452p]

Thanks Sarge for the great info. Even with the valve closed mine always seemed to have a little "residual heat" bleeding off it. At least that's what the other half tells me. So in the summer I usually bypass the heater core by looping the hose back to the engine, and same to the heater box. I have ball valves that hopefully someday I'll get around to installing.