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36 votes
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A/C loses chill when turning on blower. Why?

Welcome to the wonderful and wacky world of thermodynamics. A volume of air has heat. For example a gallon of air needs a certain amount of cooling to drop from 87 degrees to 42 degrees. An AC ...
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26 votes
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Would it be harder to install a new AC system if the old one is ripped out already for a long time?

Keep the AC system in the car until you are ready to get it repaired. There's a load of parts to an AC system and some of them are hard to access, you are likely to spend much more in labor costs ...
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25 votes
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Why is car A/C typically less reliable than fridges/freezers?

They are not even close in comparison. Your refrigerator is a small sealed unit that averages 488 BTU, the compressor speed is controlled to operate efficiently as possible, and is designed to ...
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22 votes

What is most fuel efficient at 130km/h?

It depends on several factors: The car's aerodynamics The AC compressor load Temperature differential between the desired temp and the outside temperature The SAE did an experiment, the full results ...
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18 votes
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Can a car AC unit be run on just the car battery?

I can't give you numbers or calculations without some work, but I can tell you than energy is never free. Cars have an A/C compressor that is mechanically driven by the engine because this is the ...
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17 votes
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Is it okay or useful to run heat and AC at the same time?

You're meant to. In fact, in older cars, it was automatic when redirecting air to the window defroster. On this GM control, the far right position would activate the A/C compressor. Almost always, ...
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15 votes

Vehicle AC works initially, but after driving for a while (hour+), the airflow drops to the point being ineffective

The evaporator is the component of the AC system that gets cold. It is located after the blower in the passenger cabin. As it cools the air that is passing over it, moisture condensed on the cold ...
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14 votes
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What are the dangers of refilling your air conditioner yourself?

What issues can I run into trying to recharge my A/C refrigerant myself? The most common DIY problem is overfilling oil, under or overcharging refrigerant and installing the virus that are sealants....
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13 votes

Can a car AC unit be run on just the car battery?

Well, Teslas (and presumably other all-electric cars) have A/C so it's not impossible, but A/C takes a fair amount of power. On the other hand, Teslas store a lot of energy. The A/C is something ...
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13 votes

Using sunshine to cool down the car

If you would like to do that by the use of solar panels, the problem is power. A typical car AC probably uses somewhere between 1000 and 3000 watts. A square meter of typical photovoltaic cells ...
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13 votes

Are A/C Control Panels Universal?

In a word No, not even close. Some are all mechanical, some vacuum, some completely electronic. some are combined with the infotainment device (radio) even the ones of the same type from the same ...
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13 votes

What is most fuel efficient at 130km/h?

Keeping a constant speed using cruise control with windows shut and ac on because once the cabin is down to temperature it requires little to keep it there and the ac will modulate its power needs. ...
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12 votes
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How do A/C professionals dispose of refrigerant?

When I got my Refrigerant Handling Certification from MACS many years ago, we were sworn to use a proper recycling machine, which captured everything and filtered out air, oils, and moisture. The ...
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11 votes

Is it okay or useful to run heat and AC at the same time?

Yes, it is useful, okay and won't cause any damage. The usefulness comes from the fact that the AC not only removes heat from the air, it also removes moisture from the air (because cold air can't ...
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10 votes

Why is car A/C typically less reliable than fridges/freezers?

It has to do with the type of compressor which is used. The system in a refrigerator/freezer has a completely closed unit, where the compressor is housed inside of the gas. Because of this, all the ...
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10 votes
Accepted

Should I insulate the air conditioner pipe in my car?

I understand your concern, but you will not find a car coming from the manufacturer which has insulation around the piping. If you think about it, though, it makes sense and here are three reasons why ...
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10 votes

My feet turn black

Cabin filters on modern cars use something called activated carbon (or at least some of them do) which is basically two paper / cotton sheets either side of a fine layer of carbon particles. It looks ...
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10 votes
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How to recharge my A/C

First, a word of warning. To do it right (and not waste expensive refrigerant, or risk ruining your A/C compressor), you'll have to get a few pieces of equipment. If you're just going to do this ...
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  • 1,364
9 votes

Is it dangerous not having air conditioning cabin filter?

Typically it's just a pollen filter that's more for occupants comfort. In older cars you would very occasionally get a dead bumble bee through a vent but I'd say that six days unfiltered shouldn't ...
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9 votes

Can a car AC unit be run on just the car battery?

The short answer to your question is no. As @JPhi1618 noted, the compressor is mechanically driven. Without the compressor you don't have any cooling. The AC runs by changing the state and pressure of ...
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  • 9,286
9 votes

Can running the heater with the A/C on damage your car?

No way. In fact the system is actually designed that way. The Air Conditioning (A/C) system on your car runs automatically when you are in the Defrost mode. Like you say that setup removes water ...
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  • 6,499
9 votes

Will running engine after replacing A/C components ruin the new compressor before system is recharged with freon/oil?

Your compressor should be clutch driven. If so, then running the engine won't do it any harm. The clutch won't engage the compressor without a refrigerant charge present. With the pressure at ...
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8 votes
Accepted

Is it possible to charge car battery through cigar lighter socket?

Yes, it is possible to charge the battery through a cigarette lighter socket, but there is a couple of caveats: The car's circuitry must have the lighter socket "live". It may require setting the ...
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8 votes
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Ford Escort overheats when switching FROM highway TO city driving

A non functioning radiator fan could have those symptoms. In your car the fan is most likely shared by both the radiator and AC. When driving there is sufficient air flowing across the condenser and ...
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8 votes
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Does recirculated cabin air pass through the air filter?

Cabin air filters will usually filter the air on either setting if located on the cabin side of the firewall. But even in recirculation mode, outside air will make its way in. Just be sure to ...
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8 votes

Can a car AC unit be run on just the car battery?

Yes, this is possible. Several companies (VAG, BMW) have switched to AC units that are driven by electric motors. For BMW, this is part of their Efficient Dynamics strategy, where they'll switch the ...
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  • 4,412
8 votes
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What temperature should the A/C blow?

Set these test conditions: Engine set to 1800 rpm Recirulation air direction on Fan speed on low Windows up Temp set to max cold Air outlet to dash vents Vehicle in the shade Run for at least ten ...
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  • 11.5k
8 votes

Using sunshine to cool down the car

You have a great idea! And it IS being done. Certain models of the Toyota Prius feature an optional solar roof that powers interior fans that automatically engage when the interior gets too warm. ...
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8 votes
Accepted

What's ECON and how is it used properly?

It probably has a Climate Control unit which regulates the temperature automatically. This means that the air conditioner should always try to reach the requested temperature. So when it's outside 30 ...
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  • 278
8 votes

What is most fuel efficient at 130km/h?

Fuel efficiency shouldn't be your only consideration. Rolled down windows will expose you to noise levels well above 85 decibels which can cause permanent hearing damage with prolonged exposure. ...
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