I remember a thread about how dangerous it is to be in a enclosed cab with antifreeze mixed in with the air you breath. Looking for it now.

 

Oh, No question there, stuff is poisonous.

I pulled over pretty quick and we opened our doors, and worked on the glass. Was in a driveway then. It was not good, looked greasy even, smeared unlike just water moisture fog does. Was glad I had that old (but clean) pinkish red bath towel I keep rolled up on the seat between the arm rests. It was near sunset and was in the mid 40s time we got home ... after driving through a heavily shaded national forest. My feet got cold in my sneakers though. Both hoses are shut off now at those ball valves, but I might still bypass the core with a barbed end to end union until then just to remove any temptation to try it again until I can R&R the core. Likely will then blow a little air through the core to just empty it.

Updated later this same day. I might have stumbled upon the cause of events in Post #30 above. Went out to insert a bypass, taking those worm screw clamps loose, etc .... and spied a few little cracks in the hose. I first cut the hoses back on the good side, to get rid of the cracks and the end with screw clamp impressions, and used some OEM "Tower Style" style clamps out of my really old 5 lb metal coffee "clamp can", I had kept them because as aggravating as they can be to loosen, they work. They apply even pressure, they use a 3/8" nut driver, they likely are as old as the truck, likely are original to it. Then, thinking the weight of the hoses with clamps and extra valves might be pulling the hose downward at the heater / AC box, I added a support sling up over the heater / AC box to hold the hoses up. I saw coolant at the heater core tubes where they vanish into the box in th recesses, and my heater cor holds vacuum, so maybe is OK after all.

I was looking for some of those thick spring steel clamps, but didn't have the right size ones in that can. Guess I'll buy some.

About that word "temptation"?

I warmed it up just before supper, let it get good & warm, no AF smell inside, none. Let run 20 minutes or so. Had valves open, used all positions, truck got toasty inside, but no steaming or AF smells.

 

It probably would be a good idea to flush the core with fresh water to remove any corroding sediment in the lower coils. I'm half tempted to bypass my core and flush it out since it sits in the garage, with just a couple miles on it a year, in the summer.

 

Why I put those ball valves in place on each hose, and once it warms up in early Spring until late Fall they are turned to off. The truck has the factory AC big box, all the vacuum motors work, the heat valve works, and with the valves shut, the dash vents even help to cool a little better than with those valves open I guess since the single heater valve only stops the flow through. but I guess some heat still finds a way into the core through other hose, like convection?

I know that about a year ago, I got that "extra" heater core, I tested it, I boxed it, I marked it on the box, after I padded with popping bubbles ... and I have ransacked my basement and cannot find it. I did find the messages, I remember testing it, then I guess I hid it ... well.

Went through the same thing a few years ago, looking for a plug in electric chain saw. For several days, every time I went through it ... I was looking. Then one day, done give up, was doing something unrelated, looked up just gazing, there it was hanging up.

Like ..... "Déjà vu" ... When typing those words above 30 minutes ago, I had a remembrance / thought / recollection, etc pop through my minds back alley, I suddenly recalled the "where", I got up, went down, moved a couple items out in my former "trike room" (built on unused patio to house our Gold Wing trike and trailer, etc and is now my shop apron / store room), far back corner, and there sitting high and proud on a box of Kendall GT-1 oil was a white box marked "'77 heater core".

 

I HATE THAT!! LOL I've hidden things from myself so many times when all I was doing was saving it for later use and like you, I find it when I'm not thinking about it! On a good note, apparently yrs ago, I had $500 that I wanted to save, and perhaps a few beers in, I put it under the mat in a drawer in my toolbox... fast forward at least 6-x yrs, I bought a new toolbox to put JUST TOOLS in, and in the process of moving tools and re-organizing the "old" box with things, I was cleaning the drawers and vacuuming out all crud that accrues over the years, pulled the drawer liner up and VIOLA!! Found that $500!! I love surprising myself!

 

I was cleaning out an old wallet, moved everything into a new wallet, put the old wallet in a drawer. Couple years later, saw it laying there as I was cleaning out that drawer, was gonna pitch it but decided I might better really look it over good. Hidden deep between layers, was a small white piece of paper folded up, taped up to seal it from moisture too, "cash" wrote on it. Was ten $100 bills folded in there. Oldest was the one that started it in the 1980s.

Was looking at the part numbers for these heater cores (fella here sent it to me in a box hand marked "78 Bronco") I knew just looking at it that the core in the box is right for factory AC Dents, ... but some early Mustangs, and back to 1960 Falcons. Never occurred to me.

03-05-2025: Today, with both valves open, we took it to the USPS office to mail some items, & I run the heat, then vent, and even defrost, blower on high, temperature set to max temp, it might near run us out of the cab being it was in the 50s outside, but NO mist & NO AF smells. Must have been the hose end or ends leaking into the box under the hood. I'll get some new heater hose in there.

 

So I'm not the only one that loses things by putting them some where I wont lose them.

 

Not by a long shot.


In other news, I'm gonna "let her ride" (just with new hoses) unless and until I see more evidence of need. I've give it some thought, replaying the events, etc.

I'm thinking that last year when I was putting in those ball valves in line, I removed hose clamps, cut some hose, and seems to me that I had to retighten the clamps at the heater hose to heater core connections a time or two, was leaking then from the hose to pipe area, pooled under the pipe, and I saw coolant traces running down on the outside of heat/AC box, I even saw spots on the driveway. I recall looking then to see if the pipe was deformed, it wasn't, but I'll bet some had also by then leaked into the housing past those two old "semi" seals, and has just been laying in wait. Then back on Mar 2nd, as we were riding, when I turned the heater on, maybe I went so far as to engage "defrost <> heat" and the mist was the initial blast and the green coolant created a greasy like mess on the cold windshield. Once the mess was created, it was not going to evaporate quickly, like coolant spills on the ground won't.

Another clue, the AC evap drain tube .... was a day last year, after those valves were put in, etc above, I wiped a finger on that soft hose end, it was just "damp", but was coolant. I's been bone dry every time I've checked since March 2nd. Truck is parked either level, or nose up. If some little bit of coolant had leaked in through the "semi" seals at the heater hose tube inlet/outlet .... if enough, some could have, likely would have, ended up in the bowl under the evap core to find it's way out the soft flat tipped rubber drain tube.

Anyway, it's not fogged up since March 2nd, in multiple tries.

 

Been going through this post. I’ve been on the fence about removing the big ac box and converting to non ac or leaving it alone. My ac box is destroyed so I either buy another or convert. I think after reading some of this I’m going to convert for sure.

 

How destroyed is your big under hood heat / AC box. With pieces from another one, a lot can be patched, a bit of J B Weld or pop rivets, some paint, no one will see it.

77&79F250 might have just what you need?

A few things .... going from the big under hood heater / AC box to the all under heater will mean ....

• fixing something for the big hole it will leave in the firewall. If you want the heater right, it'll mean grafting in a section of firewall from a heat only truck, of fabricating accurate holes and the recess at the heat blower motor.
• rendering the dash face vents useless
• leaving no vent for the driver as the AC trucks do not have a driver side kick panel vent as I recall (a vague recollection but seems to me that the '73 and '79 trucks I robbed of AC components did not have it) .... (please correct me if I'm wrong about the driver side kick panel vent)
• includes changing controls

Even if you replaced the busted heater / AC big box, I think would be easier to do and more rewarding, even if one doesn't put the AC parts in too. At least you keep vents and they do vent well even on a hot summer day (which is why I put a "ball valve" in each heater hose to keep heat from migrating to the core). If you are thinking of pulling it out and just plating over the hole, you'll lose heat and defrost too. If the day comes that I must R & R my 1973 heater core, I'll take the opportunity to remove the AC evaporator too.

Was a time I wished I hadn't converted from heat only to heat / AC, but then I realized the vents made it worth my while. Had I not converted, I'd still have my kick panel vents (pass side on non AC has a vent door too) but until I drove my truck without a hood bug shield (it was on the truck already) .... it was like an oven in summer, vents did not vent, so I did the AC conversion. At some point, I removed the bug shield for some reason (maybe it broke?) and suddenly, my vents worked. it wasn't cold air like AC blew, but it was moving air.

Just all that to say "think about it".

In my case ... why I drug this thread up was I thought I was going to soon need to swap a core in my truck, but I about "99&44/100%" sure not now. Maybe next year, or next fall, but not now. I can almost smell spring. I started out in Del Rio, we never had AC in our house or vehicles, just fans & vents. Moving air is great. Even now, a 90+ degree day will often find me driving with my window down, arm on sill.

 

the big flat metal plate looks like it was removed with a sledgehammer and cold chisel.
it’s missing and a lot of the housing is broken to pieces.
imagine the guys surprise when he got that cover plate off and still couldn’t pull the core out.

 

What big metal plate? Do you mean the rounded one over the right side valve cover that hides the blower? Still think 77&79F250 might have just what you need, but maybe not.

 

I have one parts truck that is none a/c. And I have a firewall that is also none a/c, if you want your patch panel cut from a trucks firewall that is for heater only.




Heater only.

The patch panel if you are going to just make it.

Once the giant evap box is out.

And BEHIND the front a/c core id the heater core, deep inside.

Bue circle is the blower motor and blower wheel.

 

yes the big tin plate that is riveted to the side of the AC box. Someone broke it off rather than drilling or grinding the rivets.
bog chunks of the plastic are missing.

 

yes I want to cut a panel from a non AC truck rather than make the panel because it’s recessed where the fan motor protrudes also there the heater core lines protrude.