The Stovebolt Site Forums The Shop Area Interiors Fresh air heater, what does it take to install in AD truck?

What does it take to install one in an AD truck that is currently equipped with the other “Harrison” round core type?

There's a cover plate near the top of your right side kick panel. That's where the Fresh Air heater gets it's air from. It'll need to be removed, then the heater bolted in its place. You'll need a control valve for the heater lines as well, and the heater lines to the core go to the right side of the firewall near the fender liner. I think Brad Allen has an install diagram. I'll see if I can track that down for you.

Here's a picture of the hose routing. The control valve is closest to the center of the firewall. Click the right arrow on that photo and it'll take you to more photos of fresh air heaters and could give you some clues on install. There may be a photo of the install instruction sheet somewhere in there. Happy hunting.

I remember seeing Brads documentation but I couldn’t seem to find it.

Here's a link to the instructions.

The heater basically bolts to the right side kick panel where the block off plate is removed and also two bolts/studs that go through the firewall. Its fairly straight forward but can be a challenge to get in place and the bolts that go into the kick panel lined up and started.

For those that have experienced both the standard recirculating heater, and the deluxe fresh air heater, is it a meaningful upgrade?

I can imagine that it's tough to get in place. This photo shows that the forward holes for the kick panel screws are slotted, so the screws have to be installed first and then the heater slipped behind the screw heads. I think you'd have to have pretty wimpy arms to be able to reach behind the heater to tighten those forward screws. Either that or a really long screwdriver that bends in the middle.

I by no means have wimpy or small arms but was able to get to them with a deep socked and long extensions. It wasn’t easy and wish I knew they were slotted before I removed them completely, lol!

Don't forget the round cover on the firewall where the motor of the FA heater will stick through.

Yes The solid round cover is removed and replaced with a metal ring and a rubber gasket were the heater motor sticks through the firewall .you can make a ring out of the solid round cover by cutting it or use some sheetmetal and use the origional solid cover as a template.

You also have to relocate the penetrations for the heater hoses, correct?

None of this seems impossible. But I’d love to hear from someone whether the “upgrade” from standard to deluxe heater was worthwhile.

My situation: My standard heater sprung a leak and needs repaired or replaced. Currently bypassed. I just bought a Deluxe/ Fresh air heater yesterday for way cheap. Haven’t even taken possession of it yet.

Gonna have to decide whether I install the deluxe or just flip it and get my standard one working.

I installed one in my 49 3600 last year. Was pretty straight forward. Believe I had the indents for the heater lines but they weren't drilled out. I'll find my photos. Edit: The photos I have are not helpful, just show the part.

The unit I bought was a refurbed original. I had to modify the hole in the firewall for the blower motor and it didn't line up perfectly with the fresh air vent in the kick panel, but with some patience and cursing (which don't usually go hand in hand but in my case they are synonynmous) I did get it.

Definitely remove your glove box.

This unit works great and defrosts my windows like a champ.

It is worth adding, this was NOT a difficult install. I did this in a couple of hours. The lines come right into the cab so if you need to service it, have a catchpan and rags handy.

Mine is 12V and came with a 6V blower. NAPA blower #M6478 was a direct 12V blower motor replacement. Probably took as long to replace the blower motor as it did to install the unit. For my purposes I used my own water valve setup (think it's the old standby from a 98 Explorer or Aerostar or something).

Did the standard recirculating heater not defrost so well?

I am unlikely to be driving my truck in cold temps very often, but I do consider working defrost to be somewhat of a safety feature (that I am currently lacking).

I equal parts cheap and lazy for secondary issues like this. Shortest path to reliable defrost is the way I will go with this project. I have a creative plan to get the recirc heater working if the deluxe one seems like a major hassle.

JW51, I had some jury-rigged heater from a 1930's car in mine when I got it. The defrost hoses were hooked up and it should have worked, but it did not defrost the windows worth a darn. Up here I need defrost even in the summer, more often than not; so it was an issue I needed addressed.

I added some info on the install to my earlier post above. HERE IS THAT POST in case you've not sure.

Thanks Peggy

No prob. I just checked all that you are doing. We may need to try to convince you to start a DITY Gallery story! (Check some of them out ... when you've got "slow down" time. )

My truck had never had a heater (or at least no indication of one) but the firewall holes for the hoses and the motor (with the cover plate) all lined up for the fresh air heater. At least mostly, the motor was offset in the hole - it cleared but was not a uniform gap around so I used some weatherstripping foam on the motor inside against the firewall and made a plate from the original solid plate to seal against the foam.

Sorry I do not know where the hoses are for the recirculating heater.

In this picture the recirculating heater hoses go through the firewall toward the center of the truck (the vertical oval hole.) the fresh air heater uses that hole for the control valve and the two on the right side of the firewall. You can also see the cover plate for where the motor for the fresh air heater pokes through.
[on edit] oops, the vertical oval hole is only for the fresh air heater. The two slightly smaller diameter holes just to the left are where the tubing for the recirculating heater go through.
I’m peeking through the keyhole on my phone to post.

Interesting... I'll have to take a look at mine this evening and see if that oval hole is marked out or blocked off on mine. I remember drilling a hole or two in my firewall last year for the plumbing, the holes for the heater that used to be in there had been "custom drilled" somewhere in the depths of time.

I did indeed have the cover plate for the blower motor in mine, but try though I may when I installed the fresh air heater that motor did not fit in the hole. It was "in the area" but hardly MOA accurate, so there was some cutting required to get it in there. Now, always possible the unit I got (refurbed as it was) was tweaked in some direction or another.

A lot can happen in 70+ years

_____
Peggy, I'll take a look at making a DITY on mine for sure.

Wonder if one could just use the existing holes if not planning to do the fancy pants control valve.

On my 54 I had a heater a/c combo installed.

I will have a look at mine tonight, it may be that I used those two holes you can see to the left in klhansen's photo in the vicinity of where the hinge would be - I remember doing some drilling, but I might be remembering that wrong.

It was easy though. I did not use the OEM valve.

The firewall pad on the inside covered the fresh air heater holes on my truck. Also where the motor goes has no hole in the pad. Only the two holes for the recirc heater had holes in the pad to match. So I'd guess that cutting holes in the pad (probably came with no cutouts from the factory) was part of the installation process for either heater.

I am not positive as it has been awhile since I had both fresh air heater cores side by side but I seem to remember the outlets and inlet tubes being in slightly different locations between the heater with the cable and fresh air flap on the front and the heater that did not have the flap. That could explain the holes not lining up.

Just installed a fresh air heater in my 55.1 a few weeks ago. My old heater wasn't working so I don't have anything to compare to, which one is better.
Definitely remove glove box, makes it a lot easier. With old heater already out, it took me maybe 2 or 3 hours to install at a slow pace. There are two heater hose protectors' rubbers that go thru the firewall, seem to be important in help keeping antifreeze out of cab from cut hoses going thru wall.
Just have a few little things left to do. Don't really like the new blower motor switch, but it is what it is.

“Volfandt” (used to post regularly here) has a series of videos on YouTube where he installs one. Seems fairly straightforward with a few little oddities here and there.

I’d love to avoid penetrating the firewall again and use a hard 90 to send the hoses over toward the driver side and out the holes for the recirc heater. I kinda doubt there’s room to do that.

Gotta find time to go pick up my new toy so I can study it.

I had a look at mine last night. The two holes in the lower left that are visible in klhansen's photo were already there in mine, I did NOT have to re-drill those as I mis-remembered. Looks like those were what was being used for the old heater in mine (which again was actually out of a 30's car, not the correct one for the truck).

Those two holes are a basically straight shot to the heater core in my fresh air heater.

I took a look at my truck. There are two holes there I’ve never noticed before. Holes in the metal, with no holes in the insulation. Kinda hard to see as my firewall is either perfectly clean or pristine.

JW51,Perfect! Those should let you install it with the hoses going pretty well straight on to the heater.

In case you haven't already found out, that insulation is flammable so I'd use a razor knife to open up the holes rather than heating up anything. On newer carpets/insulation/underlay I like to heat up a hole punch or something and it goes through like butter. But I've had that go sideways on vehicles of this vintage. (twist drills just grab everything and yank it out - I haven't tried a step bit but I have heard those work though)

Maybe a small hole saw?

I think a hole saw teeth would grab the insulation and twist rather than cutting it.

I would think a razor knife working from the firewall side using the hole as a template would be the best.

There are grommets that go into those firewall holes to protect the hoses and take up most of the clearance between the hose OD and hole size.

Yes I made some "grommets" on mine from other rubber hose, doesn't look great but I didn't have any proper grommets when I installed it (and that serves the purpose). I have some proper grommets now though; and I need to pull the box anyway as the defrost door fell off on me last year.

I agree on that hole saw, it would more than likely twist that insulation into an aggravating mess.

Finally took possession of the heater I bought weeks ago. Seems like it’s all there. Two questions:

1) What would be the best way to DIY pressure test the heater core? I can think of several ways I MIGHT do it.

2) How does one go about determining if the fan motor is 12v or 6v? I didn’t see any markings that were obvious, but I haven’t torn into it.

1. If you have a Mity-Vac, you could get some rubber plugs to fit in the inlet and outlet and pull a vacuum on the core while monitoring the gauge. Or someone has suggested clamping a bicycle tube to the inlet and outlet and using the valve stem to apply pressure. Either would work.

2. Not sure. If you put a 6V battery across it, it would likely run slower if a 12V motor, but having nothing to compare to, it would be tough to figure out.

Look at we’re the motor attaches to the sheetmetal most 12 volt motors had the spacing a little off and the holes were they fasten would have to be elongated . Old bike tube as Kevin said has been used to check for leaks.,post some pictures the 6 volt motors are a little beefier and once you take the motor off There may be numbers on the front .

Pulling a vacuum is a good idea. I can do that.

Advance, Auto Zone, O'Reilly, etc. loan pressure testing kits for radiators. Go get one and pump it up and see what happens.

Otto, Do those have adapters for a heater core that is disconnected from the vehicle?

I don't remember specifically. The last time I got one it had a ton of different plugs and stoppers and caps for all different sized openings. It's worth a try.

It seems like it would be easy to put a T in hoses connected to the outlets and pressurize the leg of the T.