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35 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 ...
vini_i's user avatar
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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 ...
GdD's user avatar
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21 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 ...
GdD's user avatar
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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 ...
JPhi1618's user avatar
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16 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, ...
Harper - Reinstate Monica's user avatar
16 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 ...
HandyHowie's user avatar
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15 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....
Fred Wilson's user avatar
  • 11.6k
14 votes

A/C not cold when idling

The AC often relies on the the electric fan near the radiator at the front of the engine bay running to cool the refrigerant. If the fan isn’t running while stationary there won’t be sufficient air ...
HandyHowie's user avatar
  • 25.4k
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 ...
Spehro Pefhany's user avatar
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 ...
I have no idea what I'm doing's user avatar
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 ...
Move More Comments Link To Top's user avatar
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 ...
SteveRacer's user avatar
  • 12.4k
12 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. ...
Solar Mike's user avatar
  • 34.6k
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 ...
Steve Matthews's user avatar
10 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 ...
juhist's user avatar
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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 ...
Cullub's user avatar
  • 1,364
10 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 ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
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 ...
cdunn's user avatar
  • 9,296
9 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 ...
Fred Wilson's user avatar
  • 11.6k
9 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. ...
End Antisemitic Hate's user avatar
9 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 ...
com2ghz's user avatar
  • 288
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 ...
zipzit's user avatar
  • 6,539
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 ...
Hobbes's user avatar
  • 4,412
8 votes

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

Another answer but less likely the solution is that the inside temperature sensor is faulty or being obstructed causing the system to think it's already cool and turns the fan down and temperature up. ...
Jupiter's user avatar
  • 3,320
7 votes

How do you detect and deal with a refrigerant leak?

A few corrections. (1) moisture in the system does NOT cause the suction line to frost up on the outside. Quite the opposite. Moisture in the system will freeze at the orifice tube or Tx valve and ...
Bob Hyatt's user avatar
7 votes
Accepted

Will cold air blow if A/C Clutch doesn't engage?

No. It wont cool without the clutch engaged. That is how it pumps and therefore cools the refrigerant. (someone correct me if I'm wrong) -- If you can see the belt on your engine, you should be able ...
user3188168's user avatar
7 votes
Accepted

When idling, AC does not work and engine overheats. What's the cause?

A few things spring to mind: confirm radiator fan operation (per user3188168's suggestion) The fans are vital in ensuring air flow across the both radiator and A/C condenser when the car is ...
Zaid's user avatar
  • 39.2k
7 votes
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How is a variable displacement A/C compressor controlled

Since this variable displacement compressor features only a clutch coil cable and no solenoid valve cables, it's "internally controlled", that is, it doesn't require any control at all from an ...
Al_'s user avatar
  • 958
7 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. ...
MonkeyZeus's user avatar
  • 1,187
7 votes

Idling motor and running AC for 4-8 hours in 100 degree heat?

It shouldn't cause the vehicle any issues. Realistically, all you'll be doing is burning fuel. The wear will absolutely be minimal, mainly because at an idle, there is very little stress put onto the ...
Pᴀᴜʟsᴛᴇʀ2's user avatar

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