Why Is The Air Conditioner In My Car Not Cold?

Hello Austin…you have helped me in the past with an automotive problem..hope you can help again. Here is all the info I know it’s hard w/o looking at car, but please respond..thanks:

Air Conditioning problem
Kia Sportage 4 cyl Two Wheel Drive Automatic

lOW SIDE =40 PSI
HIGH SIDE=240 PSI
outside temp (FLORIDA)=92 degrees (F)
topped freon off since it was not blowing cold at all; pressures read as above with blower on HIGH.

THE low side ac pipe coming out of engine firewall(evaporator) is warm, other high side pie (ac line ) is HOT to touch. What could be wrong..BOTH fans come on (ac condenser and radiator fan..car NOt overheating)..
problem seems intermittent. Sometimes car will blow cold air (only when pipe coming out of evaporator (low side is cool to touch and sweating; otherwise, pipe gets hot again and will not cool car.

Both fans(AC CONDENSER and radiator fan turn on). Car not overheating..PLEASE advise,
Thanks
Gail

Hey there Gail

Your numbers are not that far off. First I would hook up your gauges again and rev the engine RPM to 1500, and see if those numbers change.

I would expect them to be about 20-30 low side and 250 – 280 or so on high side during the heat of the day on high blower at fast idle. I am thinking you just need to add a little more Freon to the system at fast idle. Sometime you have to use a stick on the accelerator cable under the hood as you add more Freon.

I have also seen similar numbers and complaint when there is a contaminate in the system, like AIR from a recent part replacement or too much compressor oil that was added to the system.

If adding more Freon does not help the problem I would suck out the system and evacuate for about an hour then refill the system.

Please share this with your friends
Austin Davis

Hi Austin

Thanks for your help…we did put freon in at 1500 rpm…the low side ac pipe coming out of the firewall (evaporator) gets warm to touch intermittently..when it does, no cold air blows..but when it sweats and is cold to touch, it blows cold a/c. The other ac pipe is hot to touch coming out of evaporator.

Someone else told me the pressure numbers were correct but that the BLAND might be stuck near heater core??..it seems to run cold for awhile, then all of a sudden won’t blow cold anymore.

I will have someone evacuate and recharge.

I did not add any sealer or oil..just freon..about a half a can and then we stopped because the HIGH side pressure kept creeping upwards. Low side seemed fine at 40psi what is a bland door?
thanks

GH

Hello again

They are referring to the BLEND door inside the heater/evaporator case which moves when you select HOT or COLD air, it diverts air from the hot heater core or the cold evaporator core.

You can bypass the blend door as a culprit by crimping off both heater hoses going to and away from the heater core so NO hot coolant gets inside the evaporator case. This will NOT cause the car to overheat etc etc it will just not allow hot coolant inside the dash of the vehicle.

Please share this with your friends,
Austin Davis

Posted in: A/C and Heating

9 Comments on "Why Is The Air Conditioner In My Car Not Cold?"

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  1. Hains G says:

    I found out my engine was overheating and when it was it would greatly reduce the air conditioner’s ability to cool the car. Sounds logical. 🙂

    • By Austin Davis says:

      Yes, when the engine runs hot the computer tries to help cool it down and will shut off items that will cause it to run hot…a/c compressors are first in line. Also an electric cooling fan motor that is not working is a prime suspect for lack of cold air as well.

  2. Michelle says:

    I was told I had a bad fan motor as to why the a/c was not cold when I was sitting at idle.

    • By Austin Davis says:

      Yes, there is an electric cooling fan (s) up near the radiator that need to be running when the A/C compressor is on and you are at slow speeds or sitting in traffic.

      That fan pushes/pulls air across the a/c condenser to help keep the A/C blowing cold air. Not really needed as much at freeway speeds.

  3. Mike says:

    I have a coolant leak in my heater core and my mechanic says that is why my A/C is not cold???? Really?

    • By Austin Davis says:

      Maybe the coolant leak is causing the engine to overheat, which will drastically effect the cooling ability of the air conditioner. Some vehicles even turn off the A/C compressor if the engine gets too hot. So, yes he could be correct just not explaining things well enough to you.

  4. George says:

    Do those Freon stop leak additives really work? Are they worth trying or just a waste of money?

    • By Austin Davis says:

      In some cases they are worth a shot. I like to use them if there is a small leak in a seal, like on the compressor that would be very expensive to replace or on a hose fitting that is crimped with rubber and metal. I have not seen those sealers do any good on hard metal objects like a condensor or evaporator, but have seen them slow down a seal or hose leak.

  5. Matt says:

    hi…just a quick fix…try it if you like…my equinox would blow cold, then warm, then cold again…didnt matther how much or little134A and oil i put in…i didnt want to ruin the compressor when it started cycling on and off, so i took it to a shop that did an AC and OIL exchange without opening the system except for the high and low ports…they said it was important to use the same refrigerant and compatible oil (especially the oil level) for that particular compressor to function correctly…after the transfusion, all was ok…but i had a noise coming from my AC pump, probably the inside bearings are going because i tried to add/subtract/vent/etc….myself…a valuable lesson for me…i hope it holds out….good luck, matt

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