· Administrator, Resident Tater Salad
Defrost mode has automatically turned on the AC compressor to remove condensation in the air in cars for the last 20 years.
As @jblackburn stated, all cars have a compressor. It's the compressor's job to remove the moisture from the air to run the defrost option. When you put it in defrost mode, the compressor kicks in and will in turn spit dry air (no matter the temperature) on to your windshield. If it's cold outside, of course you'll want to use warm or hot air as that will defrost/defog the quickest. When a car lacks A/C, it still had a compressor. The only thing it doesn't have is the condenser which runs the coolant system to cool the air.It is pretty moist over here, however, I used to live on colder climates, and the cars there, had no ac. Just hot air does a better job at removing moisture.pure ac will cause fog.
Cars that don't have air conditioning don't have a compressor. Vehicles with heating-only climate control have regular ventilation which can bring in air at outside temperatures and have a heater core (small radiator) using hot engine coolant circulated by the engine's water pump that can raise temperatures.When a car lacks A/C, it still had a compressor. The only thing it doesn't have is the condenser which runs the coolant system to cool the air.
That hot air also has a much higher capacity to hold water vapor, adding further to the ability to defog the windshield without water running down the inside of the glass.ChevyGuy said:Cooling air make the air wetter (higher humidity). Anything over 100% becomes condensate. So, yes, A/C can both remove the water AND make the air coming out the outlet. Once the air warms up to the rest of the car, it becomes dryer than when it got sucked into the system. Running A/C and heater does a double-whammy. It pulls the moisture out of the air and then warms it to dry it out. The results will be quite dry.
I was thinking exactly the same, but didn't dare to say, as I wasn't sure of the claims that cars without AC also have a compressor (which they do not appear to have).Cars that don't have air conditioning don't have a compressor. Vehicles with heating-only climate control have regular ventilation which can bring in air at outside temperatures and have a heater core (small radiator) using hot engine coolant circulated by the engine's water pump that can raise temperatures.
The compressor on cars with air conditioning literally compresses the refrigerant required for air conditioning gas phase change process to "move" heat from one place to another (i.e. inside the car to the outside of the car). When you compress a gas it heats up. The hot refrigerant passes through the condenser at the front of the car, which is essentially a radiator that uses air passing through the front end of the car to remove heat. The cooler, still compressed refrigerant than passes through an expansion valve and into the evaporator core in the air box assembly inside the passenger compartment. This air box has the blower motor and flapper valves to direct air between the different vents.
As the refrigerant rapidly expands it cools off and condensate (moisture) collects on the evaporator core, which is essentially another radiator. This gets drained out of the car which is why on a hot day you can see a puddle of water under a car when the A/C is used.
Even on a cold winter day, when the A/C is used it still causes condensation to build up on the evaporator core which dries out air. If you left the defroster on cold you'd get really cold, dry air. Normally you use heat with the defrost mode, which sends the cold, dry air through the heater core in the air box which raises the temperature before coming out the defrost vents.
Exactly. Cold air cannot hold as much water as warm air. If you have 90 degree air with 10% relative humidity and cool it to 50 degrees, the amount of water in the air stays the same, but the 50 degree air will now have high relative humidity because it cannot hold as much water as the 90 degree air could. It's called relative humidity because it is relative to the temperature. The dew point is the temperature where air hits 100% humidity (air pressure is also an important factor for dew point, but not necessary for this discussion). At the dew point, dew forms because the air can no longer hold the same amount of water it held at higher temps.Cooling air make the air wetter (higher humidity). Anything over 100% becomes condensate. So, yes, A/C can both remove the water AND make the air coming out the outlet. Once the air warms up to the rest of the car, it becomes dryer than when it got sucked into the system. Running A/C and heater does a double-whammy. It pulls the moisture out of the air and then warms it to dry it out. The results will be quite dry.
What's the freon levels look like?????? I have never been able to see the levels. Since you say it barely works. I'm willing to be you're low on freon.So, I swapped out the cabin air filter (as well as the engine air filter).
It's a 2012 car, with 66k miles on, and the first filter swap.
The cabin air filter looked like new.
The engine filter as well, with the exception that the last guy who installed it, left his dirty engine oil paw prints on one side of the filter.
The prints were still there, but for the rest, the filter looked pretty new to me.
But none of the filter swapping did anything to the humidity.
It's very humid outside, but after a day standing outside (we live close to golf courses that fog up in the morning), the car is so humid it takes forever to clear the windows!
So my first question would be if perhaps the AC drain pipe could be clogged?
The Ac of my 2012 Cruze never has worked well!
Anything above 83, and I ramp that sucker up to the maximum, and anything above 90F outside, and the AC can't even keep the heat out!
Everything checks out well. Freon levels (or what likes) are good, compressor works...
It's just that anywhere above like 86F outside temps, it's always too hot in the cabin.
And here in Florida, it is 3/4th of the year above 86F.
One day the temperature went below 70F, and the AC just shut down on me!
I mean, my windshield was fogged, and remained fogged for most of my journey!
Is there a way to 'trick' the AC system into going a bit cooler?
I also noticed that the needle indicating engine temperatures, isn't exactly at the halfway point, but 1 line cooler. I don't know if this indicates anything, like a malfunction or erroneously configured?