Defrost with restomod AC systems - cold climate

[72-k20-burb]

I know this topic has been covered a few times, but I wanted to narrow down on the cold climate guys who have swapped.

It seems the rub is that new AC systems (Vintage Air, etc) all use recirculated air. I don't think there is a new kit out there that pulls from the exterior.. so the question is this.

How bad is it?

This is my family road trip vehicle. 95% of our driving is road trips through hot states. But we inevitably end up in Alberta, or the Rockies somewhere and I don't want to be blind.

I had a POS sedan in high school where the defrost didn't work and the passengers job was to continually wipe the windshield on the inside. I don't want that.

For reference: I have an LS swap with new compressor so no more r12 anyway. And this is a factory air suburban, but the rear air isn't really part of the issue.

Side note.. the new electronic controllers all look like 90's plastic crap. Anyone find a controller that looks somewhat original?

[Richard]

The key to defrost working most efficiently is the A/C compressor needs to be engaged. Outside air is humid most times defrost is used.
If you are worried about outside air not being present, do not install block off plate on kick panel vent and keep it open. Cowl induction will get air into cab while driving. Side note- I am not using one of these aftermarket systems.

[purple gas]

Living in Saskatchewan I know a bit about frosted / fogged windows in cold weather.
If you're not getting outside air or evacuating moist air from the cab and it's cold outside that moisture is going to condense on the inside of the glass.
I used to work in Car rental. In winter people complained they couldn't keep the windows clear. invariably I'd look at the heat controls and the recirculation button would be on.
I'd push the button to select outside air and within a block on the trip driving the customer home, the windows would clear.
Being a highly trained professional if they asked why they had problems with frosty windows but suddenly they were good I wouldn't say " 'casue you're a f...ing idiot".
You got people breathing, often snow from their boots melting, all adding humidity to the air. No matter how high you turn the heat, the glass will be cool, even cold.
Basic science, have something cold and if the air is humid moisture will condense on the cold object.
That works slightly different in southern humid climates. There's different principals involved. If it's winter driving you're talking about, if you can't get outside air into your system you can always crack a window a bit.

[clay68c10]

Just get your factory air working. Those systems work

[MikeB]

Originally Posted by clay68c10

Just get your factory air working. Those systems work

Old Air is one of the companies that sells all kinds of factory air parts.

As for defrost mode, my 25-year old V/A system blows air on the windshield like an old man with asthma. I modified it, as mentioned above, so the compressor kicks on in the defrost mode. That helps a little, as does keeping a window open and not exhaling(!) for a few minutes. And forget about bringing steaming hot coffee into the cab.

I'd hope that the latest generation systems do a better job, but I'd still try to get my factory stuff working.

[72-k20-burb]

Originally Posted by clay68c10

Just get your factory air working. Those systems work

This would be my first option, if I could figure it out.

The one thing my rig does well currently is heat and defrost. It works great in snow with all 5 of us breathing in this thing. It also isn't even remotely sealed when in recirc mode.
I'd also like it to cool with the same gusto. My repairs so far haven't been great in getting the AC to work all that well.

I'm trying to avoid trading one for the other if I replace whole systems.

AC system diagnosis is a bit beyond me, rather I've never learned it all that well. Hard to find a vintage AC guy locally.

[Joyridin]

Originally Posted by 72-k20-burb

I know this topic has been covered a few times, but I wanted to narrow down on the cold climate guys who have swapped.

It seems the rub is that new AC systems (Vintage Air, etc) all use recirculated air. I don't think there is a new kit out there that pulls from the exterior.. so the question is this.

How bad is it?

This is my family road trip vehicle. 95% of our driving is road trips through hot states. But we inevitably end up in Alberta, or the Rockies somewhere and I don't want to be blind.

I had a POS sedan in high school where the defrost didn't work and the passengers job was to continually wipe the windshield on the inside. I don't want that.

For reference: I have an LS swap with new compressor so no more r12 anyway. And this is a factory air suburban, but the rear air isn't really part of the issue.

Side note.. the new electronic controllers all look like 90's plastic crap. Anyone find a controller that looks somewhat original?

So my brother has a VA system in his car and he has driven it everywhere. I asked him about the issue with the window fogging. He said if he just puts the controls on defrost, yes, the windows can fog. He has one of their universal smaller kits in his car, not the size we would use in a truck. He said you can slide the control over to kick on the A/C with the defrost a small amount and that fixes the issue.

I have a VA kit in my truck and have never run into the issue. I usually open the kick panel vent and allow some fresh air to enter. It is very close to the inlet for the fan, so I have never had an issue. The unit blocks the vent from opening all the way, which is fine.