Always hot air blowing on my feet

[mduenas]

I can't figure out for the life of me where this hot is is coming from. The only way it is bearable for me is to have the fresh air vent open. Is this a tell tale sign that I need new heater box seals? I eventually want to put in aircoditioning, but can't afford it right now. This is with all the windows open. It is impossible to drive the truck with windows closed and not sweat myself out.

 

[DirtDonk]

Well, it's not right, but it is common.

Could be any number of holes that allow hot air through the floor or cowl or firewall, but if you're sure it's coming from the heater area, it's probably a combination of two things.
First is the heater TEMP control valve under the hood is not closing all the way. If it's an old one, this is common and a new one will, if not completely eliminate it, at least help.
The second is that the flapper valve inside the heater box is not closing all the way. The fact that you can feel air coming in is indicative of this. Either the flapper door (damper door) is not closing all the way, the seals are gone, or both.

So yeah, you might have to do a full re-seal, but check to make sure it's not just a simple adjustment or valve replacement.

Also, is your fresh air inlet hooked up, or are you pulling air from inside the cabin?

And since a lot of the control cables and knobs are sticky with rust, is it possible that your knobs are not pushed all the way in? If the controls are stiff at all, you should lube them to rule that out. A little WD-40 goes a long way here.

Good luck.

Paul

 

[DirtDonk]

Oh, and do you have exhaust headers? If so, what brand? Shorties or longies?
If old-school longies, there's a good chance that your passenger side floorboard is getting roasted and some of that is just passing around the interior.
Same for the driver's side, but not usually quite as much.

Paul

 

[kaw700zn]

Took me two years to figure out that my heater control valve was broken (here in Arizona!). 5 minutes change with a part from local auto parts store, and the life is much easier. I thought Broncos ran hot up until then.%)

For now, switch to defrost, at lest your feet will not cook.

 

[DirtDonk]

Good call on the defroster kaw. Definitely keep the toes cooler.
And we can feel your pain. A lot of things get just left un-fixed because they seem to be the natural way of things with old utility vehicles like these.

Did you get a replacement brass valve, or one of the new plastic types?

Paul

 

[mduenas]

Well, it's not right, but it is common.

Could be any number of holes that allow hot air through the floor or cowl or firewall, but if you're sure it's coming from the heater area, it's probably a combination of two things.
First is the heater TEMP control valve under the hood is not closing all the way. If it's an old one, this is common and a new one will, if not completely eliminate it, at least help.
The second is that the flapper valve inside the heater box is not closing all the way. The fact that you can feel air coming in is indicative of this. Either the flapper door (damper door) is not closing all the way, the seals are gone, or both.

So yeah, you might have to do a full re-seal, but check to make sure it's not just a simple adjustment or valve replacement.

Also, is your fresh air inlet hooked up, or are you pulling air from inside the cabin?

And since a lot of the control cables and knobs are sticky with rust, is it possible that your knobs are not pushed all the way in? If the controls are stiff at all, you should lube them to rule that out. A little WD-40 goes a long way here.

Good luck.

Paul

So much good info! The temp control knob is not factory not factory and extremely hard to pull and close. If that is my temp knob. All my knobs are blank and not original, trying to piece it back together.

Where is the temp control valve? The PO plugged the original heater holes in the firewall and moved the hoses down 7 inches.

For the time being, if it is the flapper, any cons to removing the heater box until winter again and or air conditioning and plugging holes? Or easy enough to replace the flapper door?

Thank you again!

 

[mduenas]

Oh, and do you have exhaust headers? If so, what brand? Shorties or longies?
If old-school longies, there's a good chance that your passenger side floorboard is getting roasted and some of that is just passing around the interior.
Same for the driver's side, but not usually quite as much.

Paul

I just put long tube headers on. PO had shorties the actually ran down the firewall, and had the exhaust physically running and touching along the bottom of the tranny, and passenger floor. And the temperature is less now, but still have my feet burning. I am looking into insulation and sound dampener, but can't decide on what's the best for the money.

 

[mduenas]

Took me two years to figure out that my heater control valve was broken (here in Arizona!). 5 minutes change with a part from local auto parts store, and the life is much easier. I thought Broncos ran hot up until then.%)

For now, switch to defrost, at lest your feet will not cook.

I absolutely can not wait to try this tomorrow. Especially since we have had some 90 degree days.

 

[jeff_gates]

You have hot air? I can only dream of having heat.

 

[mduenas]

You have hot air? I can only dream of having heat.

If you have an airconditioner, we can trade. Haha!

 

[kaw700zn]

The plastic one. Brass one was rusted and busted. The plastic one is operating properly for couple of years now.

Good call on the defroster kaw. Definitely keep the toes cooler.
And we can feel your pain. A lot of things get just left un-fixed because they seem to be the natural way of things with old utility vehicles like these.

Did you get a replacement brass valve, or one of the new plastic types?

Paul

 

[BroncoBoom]

Like Dirtdonk said ,
" Cables Get Sticky "
Yes ,
Sometimes they appear closed but just because the knob is pushed back in
to the dash doesn't always mean the cable is pushed all the way in ....
Corrosion , rust , bent cable sheathing , sticky valves and old parts can keep things from opening and closing as they should .

 

[Crush]

Sounds like you might have an aftermarket setup of some kind. No marching knobs and the heater core tubes 7" lower??? That would be below the inner fender and inpossible to reach. Post up some pics and we can help better

 

[half cab]

Post up some pictures of your dash and such if you can.

 

[DirtDonk]

Yes, definitely pics. If the knobs aren't stock, then the heater box might not be either.
And that lower location of the hoses might be stock and you just have other holes higher up for something else? Stock ones were pretty low behind the wheel well as Crush was saying.

The original location of the control valve is on top of the engine laying just behind the carburetor and to the passenger side a little.
It's pretty obvious if it's there, as there will be a cable coming out to meet it. If it's failed and you want to stop the flow of hot coolant into the compartment, take the hose off and loop it back to the engine, bypassing the heater all together.
In other words, use a short section of hose, or cut some off, and run one from the elbow at the top of the intake, back down to the straight fitting at the water pump.
You'll see them by following the heater hoses.

There are pics hereabouts posted up recently (very recently) showing roughly how the stock heater hoses are routed. The pics were showing a modified system, but you can still get some of your details from them.

Good luck.

Paul

 

[DirtDonk]

And if you have long tube headers and no floor covering, then you're never going to be able to figure out how much heat is coming through the heater, and how much of it is actually just radiating through the floor.

Do you have boots around any shift levers? If not, "well there's your problem right there" is a phrase that comes to mind.
Get those floors covered with something at least!

There isn't much to say one is more cost-effective than another. They all work, and they all cost. A coating like Lizard Skin is probably the most expensive (taken in addition to carpet for instance) but is VERY effective as well. Simple carpet and matting underneath is probably the least expensive and still block most of the heat, but it still costs to do it right.
Using just a rubber floor mat is next to useless when you have headers. Doing so without some other type of heavy insulation beneath it and you might even end up with a melted floor mat.

Good luck. Lots of options but you'll be happy with just about any of them that involve some kind of heat blocking material.
I've got Quality Heat Shield products beneath my carpet and it's a HUGE difference.

Paul