Car AC/Heater systems

[Ed Pawlowski]

That is the way mine works. Set it and forget it. My last cars were relatively new and the CC worked well. Can't speak for all cars on that.

I had some of that in the past. For some reason, they air would recirculate when the car was hot and you wanted to cool it down. If it is 90 outside, 120+ inside in the sun, bring in that 90 degree air and exhaust the 120 stuff. Sure, if I get in the car I put the windows down, but starting it with a remote, I want the cooker air in to expel the overheated air.

Present car is a Genesis and it has a carbon dioxide detector. It always brings in fresh air. If I do set it to recirculate, it will change to fresh air if the CO2 level gets too high where it would make you drowsy.

[DerbyDad03]

The cooker air probably smells pretty good too. ;-)

[DerbyDad03]

It sure could be the age of the vehicles. Mine is an '06.

7 - 10 years is a long time in car age, technology wise.

[Ed Pawlowski]

Yeah, until the skunk is overcooked.

[Micky]

I'd like to say that I will try, but the engine doesn't even get hot for 1/4, 1/2 mile and by then I've forgotten everything I was thinking when I got in the car. But I'll try to try.

Not this one. I used to leave it on outside all the time (I never use max AC, fan is too loud) but there's some leak dripping oil somewhere hot and the smell was entering the car, so now it's supposed to be on inside all the time, and the smell is gone. I suppose some small amount of outside air could be coming in but it's not enough to smell the oil. When I tried to leave it on Outside, I guess that was when it kept switching to Inside. Keeping it on Inside, it doesn't switch on its own as mch, if at all.

But when I fix the leak I'm going back to Outside, and it's going back to arguing with me.

Do you mean inside?

[Micky]

That's a good idea. I don't driive long distances in one shot anymore, but I remember times I was quite drowsy. Had to turn on the cold air from outside.

[clare]

Not necessaarily. On most cars if the AC is running, it's running Setting it warmer just changes the air blend. It may have a TINY impact on fuel mileage, but so small you won't be able to quantify it.

You would get even worse gas mileage using simmer gas in the cold weather. The bad gas mileage, particularly in town or on short trips, is due to the engine needing to run significantly richer when cold, and the engine taking longer to warm up. The "winter gas" does not need to be as rich to get a decent running cold engine.

Some still cut out the AC at full throttle,

[clare]

Tinted glass helps - - - Also the fact that MOST higher end vehicles with climate control have a sun load sensor that acts a bit like an anticipator

That's one thing a 14 year old car can't do - - -

On the Taurus we have to turn on the read defogger - and that also heats the mirrors. The seat gets slowly warmed by the hiney sitting in it, and gloves handle the cold steering wheel.

On the 20 year old Ranger with McGiver AC I have full control over when the AC runs and I sometimes turn it on to help clear the windshield. The fact it only has rubber mats helps reduce fogging on the inside of the glass. (doesn't hold moisture to end up as vapour on the glass)

[clare]

My 02 is pretty consistent too. (Ford) The '96 Mystique was good too. So was the '88 New Yorker. Even the climate control on the 85 LeBaron was pretty good - but on the 2600cc 4banger you could feel when the AC cycled.

[clare]

No, fresh air is standard - and MAX AC does nothing to the fan speed - or at least it didn't when I worked on Toyotas and doesn't on any of the cars I currently am aquainted with. ALL Max AC did was put the system into recirculate mode.

[DerbyDad03]

I don't recall which cars it happens/happened in, but hitting the Max AC button without a doubt increased the fan speed. I've never had a Toyota, so maybe they do something different.

It's too cold to go test the Honda Element right now. The Taurus and Civic are away at school. The Gallant has been parted out, so there's no testing that one.

[clare]

The fan sound changes because it is sucking air from inside the car instead of outside the car - Ford works the same way - no effect on fan speed when switched to MAX AC - on SOME fords the water flow through the heater core is shut off on MAX AC - on others it is not. Many vehicles have no hot water control valve.

Good solution for a Gallant - - -

[>>>Ashton Crusher]

The car makers are looking at saving another 0.004% of gas by making it so the AC ALWAYS starts on recirc no matter what you want. Recir will put slightly less load on the compressor for the overall drive.

I HATE recirc and never ever use it unless the temp is over 105 and I have to use it to stay cool.

[DerbyDad03]

I'll verify that when I get a chance.

2002, bought in 2012

It was a rust bucket, but we never had any real problems with it, and man, was it quick.

It was the rust that killed it. The brake lines started leaking so I sold it to my mechanic who was going to fix it up for use as a winter heater. Once he got into it he realized how badly rusted the frame and strut towers were. There was no saving it.

[trader_4]

Why would an AC system that draws in mostly outside air at 90F be more efficient than a system that mostly recirculate inside air at 75F?

Nonsense. The AC removes moisture from the air, just like any AC system, and there is almost always less moisture in the air that's inside the car than outside. I've never had a car that stays wet, windows fogged up, stinks, with the AC set to fresh air or to recirculate.

[trader_4]

Max AC on BMW X5 switches to recirculate, high blower speed and 65F.

Also, every car I've ever been familiar with, recirculate isn't 100% inside air. It's more like 80% inside air, which seems logical.

[Micky]

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I'm sorry. "Outside" was used twice in your line just above. It's the second "outside" I was asking about. Do you mean inside? I wouldn't post again except Trader called your post nonsense.

[Vic Smith]

Every GM car I've had MAX is a higher speed on the fan. Not just sound - fan RPM. It's obvious.

[trader_4]

My "nonsense" comment was directed at Claire's claim that without a setting that brings in outside air air the humidity builds quickly and the car starts to smell. It's like saying that a house is going to be more humid with the AC on and the windows closed. Obviously AC removes moisture, very effectively. And with less outside air, it will typically be even more effective at doing that.

Also, as I said previously, every car that I've been familiar with, it's never been possible to 100% cut off outside air. At most, setting it to recirculate resulted in about 80% inside air, with ~20% still coming from outside, for obvious reasons.

[Ed Pawlowski]

Given the ability of technology in cars today, they should be able to pull the air where it will heat or cool the fastest and switch to "outside" after for fresh air. I mentioned in another post that my car started with the AC in recirc position. It would cool the extremely hot air in a sitting car rather than exhaust it and cool the outside air. Never understood that.