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How to Fix Your Car’s AC for Free – How Air Conditioning Works

How to Fix Your Car’s AC for Free – How Air Conditioning Works


rev up your engines, okay it’s getting
hot outside and you want to stay cool in your car, today I’m going to show you
things you can do yourself to make sure that your air conditioning is going to work this summer season correctly, so I’ll explain all about how an air
conditioning system works first now air conditioning is just a heat pump, it
sucks the hot air out of the cabin of your car, and then it blows that heat
using the a/c condenser in front of your car’s radiator, the condenser is hidden
in here in the front and behind it is the radiator and the cooling fans that
cool both the radiator and the air conditioning system, now in modern cars
of course it’s all computer control, but it’s still the same basic idea, the
refrigerant is compressed by the compressor here, it’s cool that a car
thing is always the name means what they actually do, and once the refrigerant
it’s compressed, it goes to the lines into the condenser in the front, where
the heat is sucked away by the cooling fans in the radiator system, then a high
pressure refrigerant goes on the skinny little line into the evaporator inside
the car, here’s an evaporator, when the high-pressure gets into the evaporator,
it expands and as it does, it sucks in the heat from inside your car where
you’re hot, now this big tube here, it’s connected to the evaporator inside the
vehicle, and it takes the refrigerant out and sucks it back into the compressor
down here, and the compressor in an endless cycle, then compresses it again, it
goes through the condenser where it gives off a lot of heat, and then goes back
into the evaporator, so it’s basically an endless cycle of, compressing refrigerant,
then heat gets sucked out in the front of the car, then that refrigerant goes
inside the dash, where it expands in the evaporator, and it sucks the heat out of
the car, then it compresses that again and goes back to the condenser which
gets rid of the heat, it just keeps sucking heat out of the car, now when made
correctly it’s a very reliable system, but there are things that you need to check
before summer gets hot, and it doesn’t work anymore and
you get mad, and the first thing is make sure your cooling fans on your radiator
are both work and fine, because if they don’t suck all that air through there
the engine can overheat, the pressure can get too high in a compressor system, you need to make sure both fans work, so test them like this, turn the AC on full blast
and let it run a few minutes, you want to make sure that both of those cooling
fans are coming on and off, they won’t stay on the whole time, but you want to
make sure they both work and blow good you can see this one’s blowing good and
over here this one’s blowing good too, now it gets really hot here in Texas in the
summer, and I had many customers over the years say, my AC doesn’t seem to be
blowing cold enough and I check and what was happening was, maybe one of the fans
was blowing, but the other one wasn’t, so it didn’t get enough airflow, you got to
make sure that they’re both working fine and blowing a lot of air when it gets
hot outside, now the next thing to check is the cabin air filter, believe it or
not, many modern cars inside the glovebox have a filter for the AC system, you
have to fiddle with the glovebox , it just plastic so it’s real easy, out it comes and
inside this little panel you take it off voila there’s a filter, and this car is
parked under a tree, so I got one of these reusable ones, you can see there’s
a lot of crud coming out of it, you can hose it down and clean out and use it
over many times, and you wouldn’t believe how many times I’d have a customer come
to me and say, oh my AC is really working poorly and what happened was this thing
had been in there for three or four years had never been touched, it was full of
crud and hardly any air was getting sucked over the evaporator, so check your
cabin air filter if you have one and if you’re like me and park under a tree,
clean it all the time and when you’re done the cover just snaps right over and
you snap the glovebox back in, and this is one of the few times I like plastic,
because you can just bend it by your hand and snap it back in place, you know need
a bunch of tools to take the stupid thing apart with now, the next thing to check
as nutty as it sounds, is the car’s battery and here’s why,
now this Lexus maybe 17 years old, but everything’s computer-controlled, even on
the AC system, so if you don’t have the
correct voltage coming in from the battery, that whole system can go bananas
and start doing really strange things and not blowing really cold air, you want
to have your battery load tested just to make sure it’s still good, takes less
than a minute to hook it up and run the test, in this case it says replace
battery, because it’s too weak, and it makes total sense, because my wife said, the AC
doesn’t seem to be blowing as cold as it used too, well wasn’t getting enough power,
I’ll just change the battery now all cars lose a little bit of
refrigerant as time goes on, because they have a compressor that has a shaft and
there’s a rubber seal, the rubber seal has to leak a little, so that the oil
inside can lubricate the seal, if the seal ran dry, it would burn out really fast,
so they all leak a little bit, some might only need refrigerant every, ten
years or so, but they all eventually run out, a professional uses gauges to see if
it needs more refrigerant, but here’s a good check, if you find that the
passenger side is getting reasonably cool, but you go over to the driver’s
side and it’s not as cold, that often means you’re low on refrigerant, because
in this case, the evaporator is inside here, so this side gets to the evaporator
first, so the coolest air will come out here and then when it gets to the other
side, it won’t be quite as cool, so the air blowing over here won’t be as cold
as it is on the passenger side, that’s often a sign that you need refrigerant
added to your system, now if you have a set of a/c gauges and know how to use them, go
ahead and add your own refrigerant, but please don’t go buy one of those little
cans at the store and start adding it on a guess, because modern systems, they can
be off even half an ounce and they’re going to have problems if you put too
little or too much, you can destroy a system, so don’t just willy-nilly decide
oh I’m going to try to put some refrigerant in, you can do some serious damage that
way, and really if you want to mess around with this stuff yourself, you
can get a set of decent gauges for 50 60 bucks, now the last thing you can check is
the condenser itself, now this is really handy, because on this matrix the
condenser is open, as soon as you open hood there it is, if it gets covered in
bugs, you can clean it off with a little water, hydrate them, and then squirt them
off, and then you’re going to have a much more efficient condenser, and since
the condenser is in front of the radiator, it’s the first thing in a car to get
bugs and mud and crud and sometimes I’ve seen plastic bag stuck in them, most cars
aren’t open like this when you open hood many of them are hidden behind grilles
and stuff, and you can’t see in that well so get a flashlight and look around, if you
see an old garbage bag stuck in there or a bunch of bugs, get it out of the way
because if you lower that air flow, your AC goes whoop, the pressures go too high
and it’s not going to work right, so now you know how to get your car’s AC ready for
this hot summer weather, so if you never want to miss another one of my new car
repair videos, remember to ring that Bell!

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100 thoughts on “How to Fix Your Car’s AC for Free – How Air Conditioning Works

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  2. The air conditioning on my 1996 Ford Escort LX has never had anything done to the a/c and it still blows ice cold air.

  3. Hey scotty,I have an 88 safari van with dual ac,when I turn on the front ac only its cold air only comes out about 59 degrees but when I turn on the back one at the same time the front will blow out at about 50 degrees,the back always seems to blow out at about 50,just wandering what is it about turning on the back ac that makes the front blow cooler, thanks for your help.

  4. Hi Mr.Scotty, i drive a Nissan Almera , when im going around in a hot day , the ac works but after a while, about half an hour, the ac blows hot air…but this goes back to normal, after i park the car or when i off and on the engine again…any idea what the symptoms point to?

  5. Great video Scotty. I just purchased a 2nd car and it's January. I realize I better check my A/C as I have a short warranty and going through the steps you outlined with this video will make sure that in case I do have issues with the A/C, I can still get it repaired under warranty.

  6. I have a co-worker who drives without a power steering pump and a/c in his Honda Accord to make it drive faster. Is it worth it for people to do this in normal (non upgraded) sedans as well, or is the speed increase too little to justify it?

  7. Hey @ScottyKilmer I was wondering instead of yelling into your cameras microphone. Get a body microphone that would allow you to talk quieter instead of having to yell which throws me off. I like when you talk quieter it doesn’t sound like your trying to lose your voice.

  8. Thanks for sharing this information Video. But My car is Honda Civic and its AC system is generating cool and not getting trip. this Cooling is getting increase that resultant AC Vent air is getting low due icing. It seems like Thermostat is not working but mechanic checked and confirm that Thermostat is working.

    Need your help to identify the reason of AC is not getting trip and vent air is not getting low. please suggest asap.

  9. Yea my Toyota Camry you can change the cabin air filter in 2 minutes without tools. My Chevy Silverado…nope need special torx bit and remove 4 screws. Don’t have the right bit. Forget it. Stupidest design ever.

  10. I love that you made it easier to understand how AC system works. And it's entertaining, not too technical but very informative 🙂

  11. Good day scotty, i have a kia sportage 2002, im having a hard time locating my cabin air filter i already opened the glove box but didnt see any cabin filter. can u help me locate it?thanks scotty!

  12. Scotty, can you please tell me where the ambient air temperature sensor is located on a 2008 Dodge Avenger? I’ve read a lot of speculative answers on google, but nothing true.

  13. Hey Scotty when i turn my a/c on it blows hot,but turn it off an on again it works.sometimes i have to turn it on an off a couple of times before it works.I would like to know what is causing this?

  14. Scotty, this A/C video is great. As vehicles become more and more complicated by electronics and the requirement of specialized tools, it’s good to have folks like you to simplify what otherwise could seem complicated and overwhelming. Thanks. I do, however, have a question regarding your insistence on having a strong battery to ensure peak A/C performance. Correct me if I’m wrong, but I seem to recall you stating in one of your other videos that, once the engine is running, all electricity needed then comes from the alternator, not the battery. I also believe that the alternator charges the battery. Right?

  15. Great video. Any recommendations on what to check when air is only blowing out front vents and not floor or defrost vent no matter what knob setting I have it on? I have a 2000 olds bravada. Thanks.

  16. How do u know if the A.C. compressor is not working ? My air isn't cold an I wondered if there's a leak in it

  17. After taking my 1999 Honda CRV to 2 shops and and spending $350 on not getting it fixed, I accidentally found out I have a cabin filter, that’s never been cleaned or changed, (I know the original owner, she had no idea) so $15 later it’s blowing @36*F

  18. Can I replace compressor myself and drive it then in a week or two take it to a garage so they can pull a vaccum and recharge it?

  19. 2015 versa 90k commuting car ac wasn’t working right… 2 days ago overheated 🥵… turns out fan wasn’t working… replaced fan assembly wow ac working great lol

  20. Whats happening if the A/C is blowing heat poorly, taking forever to heat the interior and it doesn't feel like it heats up past a certain degree of temperature above the oustide temperature.

  21. I bought my 2009 Corolla new, the first year a rock hit my windshield and air conditioner condenser. Two separate occasions. I have had the worst luck with condenser all my life. I’m 49 years old, it’d be nice to drive a car that has air conditioner for one time in my life! UGH 😑

    Ok, I’m done complaining now.

  22. My AC works in the afternoon much better than the night or the morning. It does not make sence since the afternoon is hotter in general here in the UAE. Can you please help

  23. Thanks for making this video. I’ll have my dad watch it so that he can fix my car’s AC 😂🤷🏻‍♀️

  24. Scotty,

    My wife has a 2008 Kia Sportage V6 awd w 130k miles. We have had it since 12k miles. Over the past year;

    -I noticed on long trips the AC would stop blowing cold but if you turned it off a minute then back on it was cold again (and repeat). Dealer said the evap sensor was bad and would cost 800, have to take dash off. So I passed on that and kept driving as is.

    *Then, it started intermittently not working even on short trips. They recharged the freon or whatever. It was fixed briefly then started doing it again a few weeks later.

    *Finally on the 4th or.5th time I had it in there they said a diagnostic showed it WAS also the evap sensor. So i bit the bullet and had the Evap temperature sensor or whatever replaced.

    **Well now a few weeks later on a long trip.I realized it STILL doesnt work after 40 minutes or so and you have to turn it off or seitch between recirculate and non recirculate or turn it off and back on.

    -So now I am out 1000 bucks and my dash squeaks from them taking it off. How should I handle this???

    Luckily my other car is a 93 Toyota MR2!! Thanks Scotty!!

  25. I made a cabin filter from very good house filters, could that cause an AC system to fail? Air blows as normal, but does sound like it's working slightly harder.

  26. Thanks Scotty! This really saved me from myself. Going to the mechanic before I blow the whole system up

  27. I make a nice tricks install extra fans kits with cut out engine will live more air condition is freakyyyh freazz

  28. I checked the cabin air filter on my Toyota Corolla, just like in the video. Right behind the glove box, I pulled out the filter- and the Walmart bag that was restricting the air flow. Working like a cool dream now. Thanks!

  29. Scotty-

    I have 1996 Ford Aerostar (120k) whose AC system has gone totally empty while sitting waiting for unrelated work to be done. The system won't hold proper vacuum to evacuate moisture. Dye from a previous charge shows faint mist pattern on front of clutch face, leading me to believe the loss is at the shaft seal, if not normal amount anyway??. I'm not beyond doing a master rebuild kit if I have to, but am curious to know if I'm supposed to charge system entirely (54oz. of r134) to get proper results if I try a leak sealer first. Logistically, when will I vacuum to remove moisture?

  30. The evaporator doesn't suck heat out of the cabin; It releases cool into it. When high pressure refrigerant enters the evaporation, the pressure and the temperature drop. He should have mentioned that when any gas (freon in the case) is compressed, it gets hot. That heat is what's dumped into the air by the condenser and fan.

  31. GM annoyed my by removing the Cabin Air filters in the 03-05 truck based models. And of course I happen to have an 05 Tahoe

  32. My ac blower works but the push buttons on the console keep switching on and off at random times. Kinda like there's a short or something in the console. Any suggestions what is happening? I can keep pushing the buttons and sometimes get it to come on again but not for long.

  33. I'm sad because I need my air conditioning fix I don't have the kind of money to fix it and they charging me 100 dollars just for them to look at my car ware I live 😭😭😭 is 90 degree out and I try to put that can freezon in the L tube the arrow marks red so I don't know what do do 😭

  34. I tell you you must be a real a-hole if you dislike someone trying to help you fix your air conditioning in 90 degree heat thank you Scotty:)

  35. Thank you so much! I’m sitting in my burning hot car and have no idea about cars. I am learning so much!

  36. My ac was blowing air but it wasn't cold.i dealt with it. But now it has completely stopped blowing air. What could it be?

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