Why does A/C not work when it's hot outside?

That is not normal, you may need to get the A/C looked at by an authorized dealer. Mine blows very cold, no matter how hot outside it is.

Yeah, your system is low on Freon (R134a). Find the leak, replace the part/seal, evacuate and recharge - good as new. FYI: you should see an air temp of 32 to 40 F at the center register, all other vents closed, engine at 2000 RPM and controls set to MAX AC - High speed. You could just add freon until you get it looked at but I don't recommend fooling with a substance under high pressure that can injure an untrained person so easily. Be sure to check your cooling system for good measure too - they're related to each other.

Hi,can anybody gave me a tips regarding this problem, my aircon doesnt work, when i climb the road, a bit hill type road, that the only problem,i dont know what happen.thanks

Year? Make? Model? If you are referring o the AC compressor disengaging or the system going warm when climbing a hill: this may be normal operation because the computer will shut off the AC Compressor in a High Demand situation. Also, In many cases, the AC / Heater controls are vacuum operated and a leak in the system or failure of a check valve can cause this concern.

It is not normal and it is not because it needs freon. I have had this issue for years. I have had the entire fan assembly replaced, freon measured by a professional with the proper meters, freon added, freon drained, the lines bled for leaks, everything that could possibly be done and no one can diagnose this problem correctly. The strange thing is, when I drive in the blazing hot sun it blows out hot air. When I go through a shaded area of the road, the darn thing blows cool air. It seems to do better when I get my speed up to about 70 or 75 MPH. It's extremely hot and humid in the summers where I live. I would love to get this fixed. It is obviously a Ford issue as I have seen in the comments people had trouble with different models. Mine is a Ford Edge.

I have the same problem, Myra, but I drive a 2003 Honda Civic. Let me know if you find a solution!

If you are driving a Ford Edge Hybrid, this is normal, read your manual, because Hybrid is a vehicle that uses more battery power than a regular vehicle so when you are at a complete stop or slowed due to traffic the Hybrid kicks in which means it uses the battery pack so you are not burning fuel and the battery pack is not enough power to kick the compressor in for the AC to cool at full capacity, this is why it's called a hybrid so you will save fuel and burn less emissions into the atmosphere, now some more expensive model hybrids may have a much larger battery pack so the AC may work little better at a stop, Note: most vehicles hybrid or not cool less at a stop since the vehicle is not powering enough to push the compressor on to full capacity.

I have a Honda Civic SI Sdn, the A/C works well when it is under 70 degrees, I have added freon by professionals. I am not sure if it needs a condenser or pressure switch. If anyone has any advice, I would appreciate the help. I cannot afford to keep going to the garage.

I drive a 2011 Ford Fusion with a similar problem. It only cools when the ambient temperature is approximately 85° or lower. Above that temperature it blows extremely hot air. The compressor cuts on and off very quickly, sometimes when it's cooling but always when it blows hot. It is not low on Freon.

My Toyota Highlander had the same problem. It ended up being the System was overcharged and had air in the system from someone who worked on it. Had it professionally drained and recharged to the correct amount and problem solved!

I'm using Rexton RX5 and having same issue with AC, it doen't work when its hot outside. AC works allright at night or early morning times when its cold out side. Refilled gas and checked for leakage did servicing from professionals but issue is as is.

I just fixed this issue on my 2011 Ford Escape. It was only working when it was less than 25 Celsius outside. Essentially when it got too hot outside the refrigerant would expand (as most liquids and gasses do when they heat up) which caused the compressor to think that the 'low side' pressure was higher than it should be. So I bled off a bit of pressure from the low side WHEN THE COMPRESSOR WAS OFF! As soon as the pressure dropped the clutch kicked in and the compressor started and I stopped bleeding the system. TLDR: AC not working when hot outside, but system is charged. Try bleeding the system a bit while compressor is off. High exterior temperature may be causing excessive low side pressure which will keep the compressor clutch from engaging.

GuruS8HQ6's solution worked for me. However, with AC on, once it faults, I had to restart the car (2010 Escape) to begin the bleeding process again. It is 85 Fahr. here today, so good temps to confirm. I kept bleeding low side slowly and each time, the compressor would keep running longer. AC would run all day at lower temps, no problems at all. But, once it got hot and really needed, the issues everyone is posting would emerge. I don't know how much of this Ford system's problems are software vs hardware, but you would think the low-side pressure would be adjusted up when outside temps are high.

I can't stand this! everything above is what I am experiencing! I have spent over $2000. and no relief. Boy, they can see a woman coming from a mile away! I have a Ford Escape 2012 and as soon as it is 87 or above, the compressor shuts down. Just when I need the air conditioner. No one can figure it out! I am so fed up. What can I do?

CRC, if you look at my answer above I got mine working, as did the user below by bleeding the low side. My mom recently had this issue on her fusion and this fix worked as well. For some reason high temperatures are either causing too much expansion of the coolant, or there is a temperature or pressure sensor that is not working. However, by bleeding the low side pressure it can get it going again. Just be sure not to bleed off all of your coolant.

o.k. how do you bleed the the low side? I want to know what I am doing is correct?

To locate the valve on the low side I used YouTube videos, and then to bleed it you just need a screw or a nail, something you can push into the valve to open it. I would use a rag around your hand just to keep clean, some refrigerants are not so health friendly. The low side valve is the same one you would use to refill the AC refrigerant. So if you find a video on AC recharge for your vehicle it will show you where the valve is. Bleeding it from there is kind of like letting air out of a tire, your are pressing in the valve stem to open the valve to release pressure. Do it for a few seconds, check the AC, rinse and repeat. I do hope this works for you. If it does not you are essentially draining your ac coolant and will need to refill it if this is not the solution.

Also, as a disclaimer, refigerants are not to be inhaled or ingested. So do your best not to inhale them when bleeding them from your ac system. Bleeding your ac system should be done in a manner that does not release the gas into the environment as they are considered harmful and could contribute to air pollution in large quantities.

Thank you so very much. I am going to look into this and I will let you know if it works!

My pleasure.

Im having the same problems, in the shade or overcast days my ac works even at 90 degrees. When it’s sunny out the ac blows hot as hell. I took it in and they changed the filter, added recharge, and new motor blower. It still blows hot. I will try bleeding it, does it have to be bled every time it doesn’t work? Or just once? Also could it potentially be another leak?

Hi I am facing same problem . When the car is parked in the sun for long and gets hot, the ac compressor will not start.On turning off the car and starting several times after driving a bit the ac might come on. There seems to be no problem at all in morning or evening or if the car is parked in shade.The ac works just fine.The problem is only when parked under sun.Bled off some refrigerant from low pressure side still no releif just that ac chills less effectively now.. please help

Not only is Aaron wrong but he’s stupid. According to the clean air act, Title VI states that you can have a max fine of up to $27,500 and up to one year in prison, but this is for extreme cases. The EPA can also choose to fine you max $10,000 dollars, and there is no reward for turning someone in. Use your heads before listening to someone who claims to know what they are doing by giving horrible advice on the internet.

Have the same problem but it only started after about 140,000 were put on the vehicle. Prior to that everything worked very well. 2005 F150.So I think something in the system has gone bad. The pressure switch would be my best guess.

Have the same problem with ford explorer 2010 xlt, The ac stop working when it above 90. I have replaced almost everything, compressor, valves, pipe, nothing helps, The last garage I have been thought the problem might be from the computer engine, he suggested to renew the the computer. Any suggestions.

Check your evaporator temperature sensor, You're welcome.

My 2014 Fusion Hybrid ac works fine when the gas engine kicks in but not when the car is running on the battery. Seems more common when the car has been parked in the sun.

I have a similar problem with my 2015 Escape SE. AC cools on cool mornings and when the car has been turned off for a while. After driving for a while or when it gets warmer, I need to have the fan on and drive for a few kilometers to have the compressor clutch kick back in. Has anyone found the solution to this problem by any chance? Would greatly appreciate the help

Same problem with my MB R350. Sent to shop 4 times - rad air sent us to a German pro place- still didn’t fix it- my husband thinks I don’t know how to run the A/C as if I forgot after driving it for 8 years! But it’s just this it works in evening or cooler temps when he’s looking at it…during the day I’m dripping sweat driving this thing - at least I’m not alone! Answers make sense.

From the tons of research that I have done, it seems to be the evaporator valve. I am going to replace it and see what happens. It's a lot of work to get to it but will be saving tons of money to do it myself! It's important to go to a auto repair shop that has the machine to safely evacuate you system for you. I called around and found someone that does it for me for $20. Don't release it into the air as it will help kill our already dying planet :( Good luck! Also, I invested in the manifold gauge set (under $100) and have gotten a lot of use from it for our multiple cars. Well worth it!