Heat leaking into cab

[stang1986gt]

Not sure if this is the right section...hope so. My '69 has the factory air condition option. Air doesn't work. I set the selectors to shut everything off as indicated in the owners manual, however, I get a good bit of heat leaking into the cab. Not good with 90 degree weather! Do you guys think that the felt in the air/heater box is shot and letting heat leak through? Or, do you think that it's the valve in the heater hose? From the outside, the valve seems to be operating correctly, however, is it possible that the valve inside the hose is rusted or missing allowing hot water to reach the heater core and heat to bleed through? I'm not real sure how this system operates, so any pointers/tips where to search for the problem would help.

By the way, I had the heater/air box out once to put in a new heater core...the foam or felt looked ok to me, although you could tell it was old.

Thanks!

[FORDification]

Even with the heater hose valve completely turned off, it won't stop 100% of the coolant flow...some is going to get past the valve. That's by design, to keep a tiny bit of coolant flowing through the core to minimize corrosion. About the only way you're going to completely stop that is to just bypass the heater core completely during the warmer months, and then reattaching things once it starts getting cool enough where you'll need heat.

There are many other things you can do to keep things cooler in the cab, and mostly entails sealing things up. Check the firewall grommets to make sure they're sealing, maybe slap some duct tape over any open holes found. Make sure your door gaskets are sealing, and that any rusted areas are at least temporarily covered/plugged until they can be fixed....check the rear cab corners, sides of the cowl, the driprail area, etc. Also, since the exhaust pipe is basically right up against the floorpan, which is just a single piece of sheetmetal, heat from the pipes can really warm things up. Try laying down some heat-insulating material under the carpet/mat, and be sure to check for rusted out floorpans while you're at it, which will also let a lot of exhaust heat inside the cab.

FWIW: the foam on those flapper valves in the A/C unit is an open-cell foam, so even when brand new they're not going to stop 100% of the air-flow, just drastically reduce it.

[stang1986gt]

Thanks for the tips Keith. I've actually plugged up some of the holes, so at least I'm on the right track. However, the heat that I'm talking about is actually coming of the vents on the heat/air box. It's almost as if I have the heat set to on without the fan on. Is this normal? I checked the cables when I had the box out and they seemed to be working correctly. If it's normal, I'll just deal with it (and get a sliding rear window...haha).

Thanks again.

Any updates on your truck project?

[rjewkes]

mine did that how does the carpet on the firewall look? And the firewall itself?

Does it get worse with acceleration or is it the same?

[wildcard]

Sounds like your doors aren't closing all the way and letting heat through the duct system. Could be a weak spring not closing the door tight or maybe a seal on the door worn out.

[stang1986gt]

mine did that how does the carpet on the firewall look? And the firewall itself?

Does it get worse with acceleration or is it the same?

I'm not sure if it gets worse when I accelerate or not. My firewall and carpet (well, it's a rubber mat) look great. It seems to only be coming out of the vents. I guess I need to take the box out and check the springs and seals again (yuck).

[jor]

I would guess it's a combination of your heater valve and heater door mechanisms. I would take the valve out, get it all cleaned up and working properly. It needs to travel all the way to the off position. I just keep spraying it with white lithium grease and working the lever back and forth. Then, work the heater levers and make sure the flaps are fully opening and closing. It takes some trial and error to get them all working without interfering with one another. When you have it right, you should just feel a little bit of heat leaking into the cab. I'm not sure what year your truck is but here's a photo of the valve and levers from my 68.
jor

[stang1986gt]

I would guess it's a combination of your heater valve and heater door mechanisms. I would take the valve out, get it all cleaned up and working properly. Then, work the heater levers and make sure the flaps are fully opening and closing. It takes some trial and error to get them all working without interfering with one another. When you have it right, you should just feel a little bit of heat leaking into the cab. I'm not sure what year your truck is but here's a photo of the valve and levers from my 68.
jor

Thanks. Mine is a 69.

The photo did not come through.

Edit: Oops...yes it did...sorry. Thanks again.

[jor]

Seem to be having some issues with the photo posting this morning. Both should be there now. Also, edited my post.
jor

[stang1986gt]

Seem to be having some issues with the photo posting this morning. Both should be there now. Also, edited my post.
jor

Got it...thanks. Your valve seems to be different than mine. I've never had it out so I'll check it out.

[rjewkes]

didn't the dodge boys, mostly in the vans of cours just open the vent on the ducts sealing the ducts and leting outside air in?