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Car AC Not Blowing Cold Enough

image of car airconditioning compressor
Car Air-conditioning Compressor

I get a lot of questions about car air conditioning systems not blowing cold enough. Especially during hot humid summer days. Most people would like to see frigid cold air blasting from their small dash vents instantly upon request.

Now that this page is getting some heavy traffic I am adding some additional information and a new “Simple Fixes” video at the bottom along with some related tools and equipment for people who want to take it to the next level. So lets get that cold air back. If we get lucky it won’t be one of the three worst car air conditioning problems on older cars.

Remember, when your cars bake in the sun, for even a short time, the heat stores up in large quantities. You must remove this before it starts to feel cool inside. But what if the air doesn’t seem to get cold after 5 minutes? Unfortunately, a variety of factors affect the actual output temperature at the dash AC vents.

To follow you’ll find a few examples of common problems that I often discover when inspecting a car air conditioning system not performing as well as it should be. Without a doubt the most common problem that I find is an incorrect Freon charge. The amount of Freon in the system is extremely critical. The manufacturer installs the exact amount that is required for the system to perform at its peak.

GM Car AC compressor
GM Car AC compressor

This exact charge is so critical it is documented in the vehicle’s engine compartment down to the ounce. A few ounces short of a full charge can result in inadequate cooling under high heat loads due to lack of reserve refrigerant.

A telltale sign of this condition would be for a compressor clutch to cycle on and off faster than usual. The rapid clicking sound generated from this condition can usually be heard from inside the vehicle.

Sometimes when people try to recharge a system on their own they fill it with an AC stop leak product. To much of this stuff can make things worse. In other cases people actually overcharge the system which can cause poor cooling performance just as much as low Freon levels. In extreme examples an overcharge of refrigerant can even cause AC compressor damage and noisy operation.

Loss of AC Efficiency

image of car ac condensor
Car AC Condenser

Not as common as the Freon issue mentioned above, but one common in my area at this time of the year is a radiator or a condenser considerably clogged with bugs, dust and dirt, or road debris and trash.

When this junk starts to reduce the airflow that passes through the radiator and then through the condenser it can cause higher than normal high-pressure readings. This in turn can knock several degrees off of the output temperature in the cabin.

This is the kind of problem that slowly gets worse over time. It is very rare that people will take the time to check or clean the radiator and condenser. The fleet company I work for has made this operation part of the scheduled service operations. We have a pressure washer and we physically clean the radiator and condenser fins every 20,000 miles.

AC test guages picture
AC Test Gauges

Although there are lots of other problems that can cause poor cooling the two mentioned above are ones that I find often. If you think your car air conditioning is not blowing cold enough the first step is to check the output temperature at the center duct with a thermometer. I made a video showing how to run an AC performance test.

Make sure the re-circulation or max air mode is selected and the blower is on low speed. 40 – 50 degrees is perfect. On hot humid days in south Florida 55 degrees is welcomed. Step 2 is to have a professional connect a manifold gauge set and get high and low side pressure readings. With these readings a logical path of diagnosis can get your AC blowing cold as it should be. Read more on this subject if you plan on finding a mechanic to recharge the car air-conditioning.

I put together a repair modules section on my you fix cars website that talks about the theory and operation of car air conditioning. Understanding how the system works is very helpful for problem solving. You can also head back to this blog’s main page and get some more automotive repair information.

In this next video Pat Goss talks about things you can check at home before seeking service. This is good stuff and worth the 4 minutes. Note at the end Pat recommends professional service for charging AC systems. This might be a bit over cautious but he is right that it can be dangerous for inexperienced do it yourselfer’s. Mr Goss is for sure right that putting too much Freon in the system can destroy the compressor. It’s possible to do thousands of dollars in damage by doing it wrong! If you decide to go for it Read the instructions carefully.

173 Replies to “Car AC Not Blowing Cold Enough”

  1. Robyn

    What if it only blows cold air out on ONE side of the car? The driver side has perfect cold air but the passenger and back seat vents have hot/warm air. Any clue? My dealership (without actually looking but just giving them this info) said they would have NO idea why this would happen. If a dealership has no idea, who is going to?

  2. Dave

    Thank you for this article! It saved me a diagnostic fee at the very least. My vehicle has 82k miles and the AC does not blow as cold as my wife’s newer vehicle, which can be a problem with the 100F+ Texas heat. I took your temperature testing range, grabbed my meat thermometer and ran some tests. I used various fan speeds and recirculation settings, and saw the temperature was within range. I noticed the temperature increasing during my tests so I decided to drive around and get some air flowing over the condenser. Wow what a difference that made! My vehicle only has a small fan that covers maybe 15% of the condenser and the vent temperature would rise quite fast at stop lights even with the engine radiator fan running. I used to think higher engine speed made colder air, but that was not the case. I also got my oil changed just before this test and finally gave in and let them replace the in-cabin micro filter for $85. I am comfortable that my a/c system is running well with the new filter and knowledge of how it works.

  3. arif

    Hi Robyn, that usually happens because of a malfunctioning blend door that controls the hot and cold air mixture. Usually a simple fix.

  4. Sara

    Hi Mark,

    My car is not cooling enough the mechanic from the dealership told me I have a leak in my compressor. Took my car to another shop the mechanic can’t tell if i have a problem with a leaking compressor or the hose! then I requested to get a freon charge then my car was cooling again like it was used to. What should I do? I’m confuse I don’t know if my car really has a leak or both shop just wanted to rip me off . Or my car just really needed a freon charge.

  5. Mark

    Sara: If I understand correctly the ac was charged and is now okay. If this is the case see how long it lasts. This can be an indication of how bad the leak is. Over all it seems that a third opinion is in order. Ask friends and neighbors and co-workers for a recommendation. Make sure to notify the shop that you are there because so and so recommended them. Repair shops are less willing to loose 2 or 3 customers at one time.

  6. Aaron

    My 2005 Toyota Camry recently began showing signs of not blowing cold air like my other vehicle (which happens to be a 2001 F150 that has not had problems with the AC) . I’m thinking a recharge could possibly fix the problem (of course if it later begins to blow cool air again, then the system could be leaking). What I’m wanting to know is: Can one just simply add freon to the car or does one really need to vacuum the existing refrigerant before adding Freon? Im trying to find the quickest possible way to fix this problem on my own. Also, is there such a thing as a filter for your ac (somewhere in your compressor?) or is the only “air” filter the main cabin air filter? I appreciate your time and greatly appreciate your response.

  7. Dan

    Does not get cold until I am on the highway, city driving it never gets cold. I have a 2001 Chevy Tahoe.
    Is this a condenser or recharge issue?That is besides the problem that whatever position the thermostat is in HOT or COLD, that is what you get no matter how you turn it. To get the air to change temperature I have to turn the car off and then change the thermostat to what i want and then restart. I believe this is a control board problem but am reluctant to spend the $250 and find out I am wrong, thoughts?

  8. Mark

    Aaron: “simply add freon to the car or does one really need to vacuum the existing refrigerant before adding Freon” The total installed charge is so important for proper cooling that it’s recommended to recover all remaining freon from the system and then install the exact required amount. The problem with just adding freon is you don’t really know how much is still in there. Also the single serve cans usually come in 12 or 16 ounce. That could put you over and reduce the output temperature and or damage the compressor in some cases.

  9. Mark

    Dan: “Does not get cold until I am on the highway” This could be an indication of a condenser fan problem but other issues can cause these symptoms as well. As for the temperature control issue I have seen both control head problems as well as temperature blend door actuator motor failures on the early 2000 model GM trucks. A diagnostic at a GM dealership might be the best way to go for answers to both problems.

  10. Virginia

    Hello, Mark I have a 93 Chevy camaro and the A/C was working fine and then the compressor went out on it, I then had the compressor replaced , had a shop vac the system down and then they added freon, it worked great for one day and then now this is what it is doing… When you start the car the a/c works great then when you start to drive it above 35mph it will stop blowing cool air, (it still blows just not cold) the freon is not low had it checked by two different places.. But I don’t think it is freezing up because when the are is working it will get condensation on the line.. Plus, I can turn the a/c off and then shut the car off and start it right back up immediately and turn a/c on and it will work fine again until I start to drive over 35mph .. (not exactly at 35mph) but normally. I have also tried just turning the a/c off and back on with out shutting car off and it does not change. Have also tried turn car off with the a/c still on and starting the car back up and it still blows warm air. The only way it will start blowing cold air is to turn the a/c off and then the shut the car off and the restart …Its kinda strange to me and I have already spent a lot of money on trying to get some a/c in my car.. Do you know what it could be I have been to several shops and I just don’t think they know that much about a/c to be an a/c shop. please help. Its really hot here in Florida and I am in my car all day.

  11. Mark

    Virginia: Hard to make a call on your problem without hands on diagnosis and pressure readings. The shop should be able to determine an electrical problem from a freon or system problem. I can say that the most common thing I find after replacing a car AC Compressor and have these kinds of problems, is clogging of the orifice tube on GM cars.

    This comes from improper flushing procedures. Vacuuming down the system is not good enough with an internal compressor failure, you need a liquid AC flushing chemical. As for not being able to reproduce or solve the problem it would seem you need to physically drive with the mechanic. Take him out on highway 95 and make him sweat! No mechanic should give up when the going gets tough.

  12. Virginia

    Thanks Mark, the readings low side was 30 and the high side was around 350-400 I thought that meant it was over charged but the shop said that it is not.. But also it did something else to that I forgot to mention it has a pressure release valve on the compressor and it released freon I heard it do it..

  13. Mark JM

    I’ve got a 2010 Ford Fusion, 44k miles, has dual auto-temp conrols. AC temp out of the center registers was around 58-60 degrees, outside temp 95 and humid.. my 94 Taurus and 99 Taurus both blow at 38-42 degrees same outside temp. 99 has auto-temp, 94 is manual.. dealer replaced compressor and associated part on 2010 Fusion, said compressor was failing??? New parts still work like old parts, temp is basically the same 58-60. On a cooler day, register temps will be lower down near 50. This car came from the Carolinas, was actually used by Ford rep, ran between Carolinas and Georgia.. car is otherwisw in pristine conditon. Any ideas???
    Thank you

  14. dave

    My ’96 Ranger is now blowing only hot air. For the past month or so it blowed cool air at low speeds but hot air on the highway. I just tried to charge it with r-134, but saw that the pressure was a bit over normal. I see cold sweat on the valves out of the evaporator. Does it sound like the compressor/condensor, or more like a clog in the system? The compressor runs continuously and does not cycle when the A/C is turned on. I live in 100 degree weather. Thanks.

  15. Mr ketter

    I changed my ac compressor about 5 times because everytime i changed it, it would get clogged. But they finally fixed it. However, my ac was still blowing hot. So I was told that my radiator is probably not doing a good job in cooling my engine as air does pass through the radiator to cool it down. And i knew my radiator was old, and it actually had a little leak. But once I replace my radiator……BOOM! AC IS BACK TO BLOWING COLD AGAIN!

  16. Grayson

    Hi Mark,

    2006 F150 Crew cab with 90,000 on it. A/C works great 95% of the time. Usually gets down to 42-44 while driving. The problem I have usually occurs right after starting the engine or within 10-15 minutes of an engine start and only occurs at idle/low RPMs. The air will cycle hot cold hot cold until i start driving. I’ve been to 4 shops (2 dealerships and 2 neighborhood shops) over the last 12 months trying to get it fixed and no one can figure out why. The funny thing of it is that right after they’ve supposedly “fixed it” the car usually sits outside the shop in the hot sun, I go pick up the car and voila, the issue happens right on the spot before i even leave the parking spot. The guys who worked on it are dumbfounded and after a couple days of trying to find out the issue they usually just give up and call me to come pick the truck back up. I’ve had the clutch replaced, system recharged twice, condenser and manifold lines replaced. The times the problem rears its ugly head is usually if I just sit in park after the car has been in hot sun. It will start blowing cool air, then click off and blow hot, then click on and blow cool again etc etc etc till i start driving down the road. The other usual cause is if it’s been sititng in hot sun for a while and I go for a quick trip to a drive thru (less than a 5 minute drive away) it will do its on off on off stuff while i sit in the drive thru. Everything checks out at the moment from pressures to no leaks etc (according to the shops anyway), yet I can still reproduce the problem on a regular basis (provided the hot weather is available). Everyone’s first diagnosis is either the clutch or low pressure, but both of those have been addressed. At first I was kinda pissed because of the time and money lost, but now this has turned into something kind of amusing watching everyone scratching their heads at my perdicament. Any help or suggestions would be much appreciated.

  17. Roman

    I have a 2002 Chevy 2500 Duramax. The AC when on max cold only gets cool. If I change to temp setting only one click toward the heat, still well within the cold air setting, it starts blowing hot air. I have take then housing off below the dash and it seems to be blowing cold air but changes to hot as soon as I make the same temp setting change on the AC controls. Is there some kind of “door” that is not moving or could you give me some other advice.

  18. Mark

    Roman: In the end you will need some hands on diagnosis. But I can say I have seen blend door control motor problems on some of the 2002 Chevy models that have symptoms similar to what you described. The GM dealer can test these motors with specialized equipment making them the best place to go for quick answers to problems such as yours.

  19. patrick

    I have a 2008 ford fusion that I can start 15 to 20 minutes before I need to leave for work. but when I come back out it is still cold and still frosted. then when I begin driving it begins heating up. doesn’t do it every time.

  20. dar dsa

    Hi Mark – appreciate your time and advise. My Honda Civic 2003 LX AC has every 2 years stopped putting out cold air. While it was under warranty the dealer replaced the O-ring and the AC blew cold air. 2 summer later (when the warranty had lapsed 6 months) it was again not blowing cold air. Honda agreed to pay for parts $60 if i paid for labour $200. This time they replaced a valve. 2 years later again it was not blowing cold air. this time i took it to an independent shop. they told me they could detect no leak with dye and UV, recharged the system and sent me on my way (and a $300 bill). the system blew cold air that summer and the next but again this past summer it was no longer blowing cold air. I dont want to spend another $300 to be no better off than before. Any advise on what the problem might be or am i better off just re-charging the system every 2 years?

  21. Mark

    Dar Dsa: Very slow Freon leaks are the hardest ac repair to resolve. A 2003 Honda Civic does not hold much freon to begin with. If it takes 2 years to leak out this is a very very slow and hard to detect leak. I would give the shop that installed the dye another shot. If they did install the dye correctly there may be a chance they can detect the location at this time. It boils down to equipment and techniques used to locate the leak by the shop. Finding someone with the skills, equipment and patience to bear down and fix your problem will be challenging.

  22. Peter

    Hi Mark,

    I have a 2005 Nissan, Altima. Driving home on Saturday my AC would not get cold. Now it seems to be working again. What do you think would cause this? Thanks for your help!

  23. Linda

    I am a single women and I own a Nisan Sentra 2003. About a week ago on my way home my ac quit blowing cold. On Saturday I took it to a shop and they told me it need to be charged. I paid them to charge unit and it was blowing cold. I got about 5 miles from the shop and it quit blowing cold so I went back to shop and they said now I need air compressor. The guys never got under car to look at compressor!? I left would not let them do anymore work on car. I tried running the air again and it started cooling but it really pulled on the engine(felt like I was climbing a very high incline) then felt the engine change and then air got warm and it seem do this a lot so I shut ac off. So how can I look or test my ac to see if it is really my compressor? I am tired of companies taking me for money by telling things that are not true.Thanks,Linda PS: I have sent a complaint in to the BBB on this company and I am trying to get a hold of manager or owner about my refund for charging.

  24. Mark

    Linda: Sorry to hear about your AC troubles. There are several ways for an experienced mechanic to diagnose a compressor. Your problem is complicated to say the least. Finding a trusted competent Mechanic is the best way to go. Unfortunately improper AC charging can ruin a compressor but this will be almost impossible to prove. There is a video from the today show about AC rip offs on Note the video starts after a 15 second commercial. It’s worth watching. Here is the link

    Wish I could do more but this would require hands on diagnosis~Mark

  25. KP

    recently, i have changed a new ac system on my car. everything is new except for the compressor (reckoned) but the mechanic told me it is still in good running condition. Now, the ac is not so cold as expected and it doesnt blow really strong. so, it is because of the compressor is not doing its job?

  26. Mark

    KP: Although you did not provide enough info to answer the question you did say “not so cold as expected and it doesnt blow really strong” This symptom use to be on the ASE car air conditioning test. The answer to the test question is the evaporator is freezing up. This reduces air flow and output temperature when ice clogs the evaporator. As for whats wrong with your car I have no Idea. You should probably work with the people who replaced all the parts to resolve the issue.

  27. Odion

    My car doesn’t move fast when AC is on, when im on motion and i put on the AC, the car speed will reduce and when i turn the Ac off the car speed will increase, what could be the problem?

  28. Christopher

    My car was just recently repaired and had been out for about 2 weeks. I am sure it had been sitting in the yard of the shop, baking in the sun. The a/c did not blow cold at all when I went to pick it up and drive it home. This morning, it was a bit cooler as my car is parked in a garage normally. However, it is still not COLD. So, I went to Autozone and got the stuff to recharge the a/c. When I hooked it up, it did not take the solution from the can at all! I thought normally it was supposed to suck it right up? The can got cold, but remained full. If the freon does not need charging, does it not take the solution from the can? Please advise!

  29. Mark

    Christopher: When people say “car was just recently repaired” I usually advise they return to the shop to have the issue evaluated. AC comebacks are not unusual because slow leaks are hard to find. As far as the can situation, If you followed all instructions on the can to the letter and it will not go in, then usually this is because the compressor is not running. this can be caused by a long list of problems including not having it turned on.

  30. Julie

    My 07 Corolla has cold air but is not blowing as hard as it used to. I live in Georgia and it is HOT. It Sounds like it blowing hard but is blowing very lightly. Not sure what it could be.

  31. Mark

    Julie: The most common cause of low air flow from the vents is a clogged cabin filter. Especially if the one on your 07 corolla is original equipment. Instructions for service are in the owners manual.

  32. odddon

    Thanks for posting all of this info. Now my situation 🙂 2000 Dodge Stratus. The fan speed/AC button part of the climate control panel went out, so I got a used control panel and installed it. I hooked everything up exactly the same way as it was on the bad panel, but now the AC doesn’t get as cold as it used to. The temperature cable is at the same adjustment as it was before. Also, on a 3 hour drive last week, we turned the fan down to low for a while, but when we turned it back up to high, the fan got louder (like normal) but the airflow remained very low. Any ideas?

  33. Mark

    Odddon: Although I’m not an expert on this year Dodge ac system it sounds like a trip to the dealer might be in order. On some vehicles the control head and the door motors that operate the temperature and blend doors needs to be calibrated to each-other. This operation usually requires a dealer special tool. Don’t know if this is for sure your problem but when they are out of calibration symptoms like the ones you described are common.

  34. Julie

    Mark, Wow, what a difference, you were right! There was a filter behind the glove-box that I did not know about. I now have LOTS of air! Thank you so much!

  35. Mike

    Mark, I have a 2002 Nissan Frontier. Sometimes the AC blow cold air, but sometimes it blows warm. I can sometimes trick it into blowing cold again by toggling the ON/OFF switch. Sometimes it decides to start blowing cold air again without any input from me. Thanks in advance for any help.

  36. criag

    Hi! I have a 1996 Jeep grand cherokee laredo, and the ac system dosent really make the air cold at all even on high mode. Here is what I noticed, it easily works on a cold day, it sometimes will take a hour before it gets cold in the car, and if I drive fast sometimes it gets colder. What do you think is causing the problem

  37. Gareth

    Hi Mark

    I have a 01 BMW 320ti Compact and recently have had the air con recharged but the next day after getting it recharged the air con now seems to blow cool air but not as cold as it was after getting it recharged. What could the possible problem be? I have been told it could point towards a new compressor but wanted to check any other problems before spending all that money.

  38. Mark

    Gareth: Of course logical diagnosis of the problem is required BUT. The symptoms you described would indicate a leak in the system not a compressor problem if it worked after the proper charge was installed and then warmed up the next day.

  39. Carl

    HI Mark

    This thread is a bit old I see but I have a question for you. I have just bought a used Ford E350. The seller had just fixed an AC leak, by replacing a pipe that had been worn through. He’s a home mechanic and I know he used the fluro dye to find it. But having spoken to a friend who works on his car a bit, it seems if the AC system was empty (unpressurised) for a time, its really critical to vaccum the system out and replace the filter/drier. I’m not sure if this was done. The AC blows cold, but not ice cold, and it seems to be cooler when the fan is on high. My question is, if this vaccuming and replacing of filter hasn’t been done, is it worth me having it done now? I’ve only had it for a week so the AC hasn’t been used that much. Or it is too late and any damage that has been done is now done and I just wait and see over the next few months if the compressor etc fails? (I will be driving the van full of people in 100+ temps for the next month on a road trip, so I would hate to completely blow the system when we are miles from home).

    Thanks in advance for any advice you can offer!

  40. Mark

    Carl: Hard to advise on your complex situation with many unknown variables. I can say that both the dryer and vacuuming of the system is meant to remove moisture. Moisture is the enemy of AC systems and can continue to corrode internal components as time goes on. So from that perspective It would seem worth it to replace the dryer and perform a recycle and charge. Incorrect freon level is another huge item that can drastically affect output temperature. But again tough to provide definitive answers with so much unknown.

  41. Chris

    2003 Chrysler TC LXi with 130k miles. Recently took a 800 mile trip from GA to MI. AC worked fine all morning but somewhere around midday I noticed the air coming out of the vents was definitely not cold anymore. It was mid 90 degree temps outside by this time. The driver’s side has not been cooling as well as the other zones for a while now but now all zones were blowing kind of cool but nowhere near normal cooling temps. This problem went on for the next several hours. I noticed at one stop to eat that there was a large pool of condensation water under the car after it had sat for about 30 minutes which led me to believe that at least something was getting cold. I would occasionally feel a quick burst of cold air coming from the vents and turning off the AC button and then turning back on would result in about 20 seconds of cold air but then it would return to just blowing room temp air, not hot air. We were still driving at sunset and all of a sudden the air got very cold again. Outside temps were still mid 80s but the sun was no longer beating on us. I also heard some plastic “popping” noises from behind the dash like something had been stuck and had just freed itself. The AC worked well during small, hour long or less, trips around time while in MI. The “issue” returned during the trip home to GA. The next day the wife is driving around town and says the AC is working normally again. Any ideas or suggestions regarding what issue(s) I might be looking at here? The driver’s side is still not cooling as well as the other zones. Relays? Some sort of temp sensors? Less than $500 fix? Thanks.

  42. Mark

    Chris: Sounds like issues with the climate control in relation to the temperature control and blend door motors. I am not an expert at this year Chrysler version of the climate control system. I would take this to a dealer only for diagnosis because they have a specialized tester (DRBIII or StarScan) to diagnose and calibrate this particular system.

  43. Lorie

    AC 1999 Jeep Wrangler 4.0 straight 6. Replaced compressor, put 6oz of Pac46 oil turn it manually. Replaced all hoses, accumulator. Had it vacuumed and R134 in professional temp 225 high low 47 inside temp 70. Also replace switches, ac control unit. Took it in for a diagnostic…no leaks can’t figure out why its not working i.e. firerstone. Replace radiator, all hoses, temp gauge and house unit, water pump….no leaks…oh new belt…still hot air ….what is going on…..the compressor was re-checked, good. what else can it be? Please help its hot in Sacramento 100’s

  44. Mark

    Lorie: Unfortunately the list of things that could be wrong is long. The low pressure reading you provided is a little high about 10 psi past where I would shoot for. This can be from overcharging or more complicated like a compressor starting to fail. The amount of Freon in the System is so critical for diagnosing whats wrong. I know my Firestone in town is kind of weak. AC is complicated and sometimes people say they are experts when they are not. Even if the Freon side of things is perfect the car side can cause issues. Temperature door calibration, Condenser clogged with dead bugs. Evaporator blocked or freezing up can all cause this issue of not cold air.

  45. Mark Rinen

    Hey mark: I have a 98 Honda civic evacuated system changed ac condenser and evaporator then went to sears to recharged my ac and for some reasons the tech said that its my compressor both high and low side are in specs and also temp only goes down to 60degeees I just want know if its really the compressor before dumping money into a new one please help me.

  46. Mark

    Mark: Not enough info to guess on the condition of the compressor but if the pressures are good and the compressor isn’t noisy then i would seek a second opinion before doing anything.

  47. Ed

    I have a 2006 Ford E350 van I bought used in 2011 with only 5,000 miles on it. It was used very little and the company decided to sell the vehicle. It was like buying a brand new truck for 1/2 price. Anyway, at 35,000 miles, I have an A/C venting problem. The venting will default to the defroster when I accelerate. Actually will do it most anytime. Occasionally it will go back to the dash vent for a little while. Ford tells me there is a part on the firewall, hard to get to etc. They want something like $900 to fix a $40 part. Can you give me an idea of what to look for and where? Regards, Ed

  48. Mark Gittelman

    ED: It would seem a common problem on your model. After reading through some forum posts it seems like a tough job as the Vacuum Reservoir is located inside the evaporator case and possibly riveted on? What I did see was not everyone had to replace the storage tank. There is a check valve in-line near the canister that’s more likely to fail. keep in mind any vacuum leak in the HVAC hoses can cause this problem although it would seem more likely the Vacuum Reservoir or check valve is the culprit.

  49. Larry

    I have a 98 Express van, 5.7 V8. AC was not getting cold. Bought a recharge can with hose and gauge on it. Recharged the AC but it still won’t get cool or cold. Pressure goes from 10 PSI to 180 PSI. Could I have a blocked orifice screen and a bad accumulator? Larry

  50. Mark Gittelman

    Larry: To answer your question directly yes it could be a clogged orifice tube. Unfortunately, the most common reason for a clogging orifice is debris from an internally damaged compressor. Other things can cause the type of pressure readings you described. I recommend Some professional diagnosis before opening the system to check the orifice.

  51. Valerie

    I have a 2012-yeah, you read that right, Ford Escape with an AC that blows hot when it’s hot and cooler when the temp drops. I live in South Florida and it’s June. I haven’t used an AC pressure gauge, but would a clog cause this to happen? Should it be flushed and refilled?

  52. Mark Gittelman

    Valerie: I think it’s worth getting a professional diagnosis as many things can cause this type of issue. Most common would be a system low on freon due to a small leak. Connecting a set of gauges and getting some readings is the best place to start.

  53. Michael

    We have a 2002 Dodge Grand Caravan. Recently we replaced the Condenser, dryer, and a hose due to leaking and a fender bender. My fiancees father charged the system but his gauges kept leaking throughout the process. He also didn’t add any extra oil to the system so the compressor has been a little noisy. I picked up 3oz of pag oil and a refill hose with the gauge on it. I added the oil and the compressor got quiet like it used to be. The thing is it was showing as if it were low on freon with the temp outside vs what it should have been in the V on the gauge. So I picked up a can of R134 to charge it up some. It now blows warmer out the vent (off recirculate) then it did before the freon was added. Also I have a question about how to properly read this gauge. The needle is now in the V when the compressor is engaged but it jumps into the red when it’s not engaged. Is that normal or is it overcharged now?

    Just a bit more information. On Friday (prior to me adding any extra freon) we were driving along and slowly the amount of air coming out of the vent was decreasing. So much so it was originally on recirculate but was blowing as if it wasn’t and on the lowest fan setting. The blower motor was still sounding like it should but the amount of air coming out of the vent was minimal. I didn’t know if the shaft broke or something on the blower motor so we pulled into an AZ (Blower motor is LLTW from them) I pulled the motor out and turned on the ac. It was spinning just fine.

    During this time of taking out and testing the blower motor I assume the exaporator was frozen over because now it’s back to blowing as it should. Would low or too much freon cause it to freeze up blocking the airflow to the vents? Remember I didn’t add any freon to it yet at this time. Nor the 3 oz of extra oil to make up for what wasn’t in the dryer, line, and condenser that were replaced.

    • Mark Gittelman

      Michael: You provided a lot of quality information about your issue. An evaporator shouldn’t freeze up no matter the oil or freon charge level. This would be an indication of an orifice tube or expansion valve problem. BUT I would start with an evacuate and recharge. There is nothing more important then the total installed charge. You have no idea how much is in there now. It sounds like it’s slightly overcharged? Going to a trusted shop and getting the level of refrigerant right is the correct starting point.

  54. Tee

    I have a 2003 ford taurus and I just got my my ac compressor replaced and my ac system evacuated and recharged. It worked for only one day now im back to hot air 🙁

  55. Eric

    I bought a used 99 Nissan Altima GXE with 115,000 miles on it recently as a get around car. The air worked fine on 2 test drives on separate days before I purchased the car. Both times it was cooler than when I started it 2 days later in extreme hot temperature over 100 degrees. The air blowed fine but never got cool. I called the person I bought it from and he swore he never had problems. Then the next am I went out and started it while it was still cool out and it worked fine. I have to store it outside cause my garage is filled w 2 other cars. Please let me know what I should do. I have it covered w bed sheets cause its under a tree. Could that be detrimental?

    • Mark Gittelman

      Eric: It’s a tough call, not knowing the history of AC maintenance or repairs. Sometimes systems that are only inoperative in high temperatures have pressure issues. Since one of the most critical factors involved is the total charge in the system, I would probably start with a recover and charge from a trusted shop. Then they can run a performance test putting them on a logical path of diagnosis.

  56. Eraldo

    Hi Mark, nice information that you provide here man, I really appreciate. I live in South Florida and my 2010 Chevy ac does not work when it is on the first stage, but when I put on the 2nd stage or above it works really strong. In the end I have 2 options, get toasted or get frozen hehe.. do you think it is a problem related with the pressure inside? Which part should I take a look better ? And also, should I buy only OEM or a quick research in the aftermarket worths the price? Thanks man and if you have any business here in Miami let me know.

  57. David Branch

    I have a 03 Jetta with the 1.8T engine, with 180,000 miles. My a/c works, just not real well. . On days when it is 80 degrees outside it blows about 50 degrees at the vent and holds pretty steady. When the outside temp reaches the low 90’s it will get down to 50, but then goes up to the low 70s, then cools back down. When I can watch the compressor, it is staying kicked in while the vent temp is going up and down. When I hook up my gauges, the low side runs about 55 psi, and the high side runs about 185. So I thought the low side was too high. Let out pressure and the high side drops faster than the low side. When the pressure on the low side gets to about 37 psi the high side is about 80. Both of the radiator fans work. I am not sure if I need a new compressor because it is just not building up pressure, or if something is just stopped up somewhere. Where is there a filter in the lines? What do y’all think?

    • Mark Gittelman

      David: I’m not sure if the 03 Jetta has an orifice tube or expansion valve, but this would be the most likely place for a clog to develop. You might also be onto something when you mentioned the compressor being worn out as well.

  58. Justin

    I have a 2006 vw passat. Recently, I had the thermostat replaced for approx 300 dollars. At the time I took it in, the ac was working flawlessly. When I picked it up, noticed the ac wasn’t blowing cold air. Of course, when i presented the issue to them, there was a CLUELESS reaction on their part. However, I started hearing a steady, but sporadic clicking sound under the dash right by the middle vents above the radio. After about 5 minutes, the clicking noises stopped. I’ll be taking my car to another ASE certified location which has a very good reputation, so any input would help so I can be “somewhat” familiar with the results when they tell me whats going on.

    • Mark Gittelman

      Justin: The clicking sound and the interior area you describe it coming from sounds like the temperature door motor. Maybe when they replaced the thermostat they turned on the heat to allow coolant to flow through the heater core to work out air bubbles and it got stuck (clicking)? Otherwise it’s hard to connect the issue with the repair.

  59. Ron Morgan

    Mark, Great info. My issue: 2005 Jeep Wrangler Rubicon, 4.0L. New condenser, new compressor, new dryer, new evaporator. r134a. Installed by certified A/C tech. I can’t get the system to cool below 65 degrees when it’s hot and humid (+90 degrees and high humidity). At or below 85 and low humidity I can get it to cool down around 45 at the center stack. I have a set of MasterTool gauges I use for checking all of my auto A/Cs. Today it was 100 degrees ambient. Low side pressure was 45 and high side was 225. Compressor cycles on and off as it should, but system will not cool below 68-70 in the garage. I added a little R134a and raised the low-side to 50-52, high side stayed at 225-227, compressor stops cycling. Still won’t cool down. My son has an ’03 Wrangler, exact same set-up, and his will freeze you out no matter the ambient. Mine used to before it was “repaired”. I can take it to another A/C shop, but thought you might have some advice first.

    • Mark Gittelman

      Ron: The low side pressure is a little high. It could be slightly over filled or the new compressor might not be as good as the old one. You didn’t mention the the circumstances of the original compressor failure, but if it spread debris through the system it may still have some in there causing a partial restriction.

  60. Carmen

    My air conditioning is only cool when I am sitting still or going and low speeds. When I am highway driving it blows warm or environment temperature air and I use way more gas when I have my air on at all. What would you suggest I do to resolve this issues. I am afraid of being charged extremely high prices just to diagnose.

    • Mark Gittelman

      Carmen: This type of AC complaint usually heads towards an air flow problem. Example: A Camaro or Firebird with a missing lower air dam or any model car that had the air dam removed by a parking curb.

  61. Gary

    Hi Mark, I have a 2012 ford fiesta that started blowing air. It works best at cooler outside temps and freeway driving. However, that’s no guarantee either. Naturally, Im out of warranty at 60k miles. Cant I just start at a Jiffy lube and have them check the freon level and system cooling check? I hate to start spending a fortune and still have the problem.

    • Mark Gittelman

      Gary: I see quite a few complaints around the web with the Fiesta AC systems. Condenser fan issues along with blown fuses and leaking freon are just a few of the resolutions. So you have to start somewhere with an initial diagnostic. I would recommend seeking a qualified tech with some AC expertise under their belt.

  62. Dee Almalvez

    Hi Mark, My 2011 Mitsubishi Outlander Sports ES (manual transmission) was involved in a left front fender car accident May 2014. After all the needed repairs has been done, the car is running smoothly. A side note, during the repair process (3 and a half weeks) I would periodically visit the body shop to check the progress of the repair. On one of my visits, I asked the technician supervisor why the entry Air Condition Condenser Assembly (ACCA) has an asterisk beside it, his reply was, the ACCA part was a replacement part, I asked why not use original manufacture equipment (OEM) like the other items on the list. He said that my insurance company approved them of using as such and it’s compatible and cheap to do it plus they (body shop) will backed it up with a lifetime warranty. I took his word for it and like I said above, the car is running fine and smoothly after it was delivered to me. Now, fast forward to February 2015. As a habit, I would turn on the AC of my car during Chicago winter for at least 60 seconds just to get the freon moving. Prior to the accident, I would turn off the AC within 30 seconds because the blast of cold air is too much. Not this time, the air coming out is not cold at all. I was driving for almost an hour with the AC on the maximum mode and the only thing I noticed was a little tinge of coldness. After I get home, I tried the AC of my daughter’s 2004 Lancer and within seconds it was frigidly cold. I’m not an expert, but, something is amiss. With that being said, my question is, do you think the replacement ACCA is the culprit? The slight cold air I’m getting from it appears to be a leak somewhere? I just need to hear your professional input, before I have a diagnostic done to it.

    • Mark Gittelman

      Dee: It sounds like you should go ahead with the diagnostic. I would be less concerned with the quality of the replacement part and more concerned about the procedures used on the labor side. The first thing to find out is the level of freon in the system and then go from there.

  63. John

    Hi: I have a 2007 Toyota Camry XL V6 (100,00 miles) that blows hot air for about 15 minutes then cold air. This only occurs after the car sits for 10 hours or so. When the AC finally blows cold air, I can stop for and hour or so and it will blow cold air. But let it sit over night, then hot air again. I took it to the Toyota dealer the first time and they said there was too much Freon in the system; took it back a week latter (same problem) and they said the expansion valve was bad; about a week latter I took it back (same problem) and they said it was the evaporator. After spending about $2000, guess what: same problem. The Toyota dealer seems clueless or at least equally frustrated. No other known issues. Any ideas on next steps besides selling it?

    • Mark Gittelman

      John: A bunch of things can cause this issue. Top of my list would be the expansion valve, but they already replaced that. The next things that come to mind is the compressor, condenser fan operation or air, water and debris floating around the system. Unfortunately the small window of time to pin down the problem is when it’s blowing warm air. This means leaving the car overnight and hoping the mechanic realizes he will only have 1 shot to get it diagnosed per day. Then leaving it an additional day to confirm its fixed.

  64. Jennifer

    I have a 2007 Toyota Camry Hybrid 4 cylinder engine. The ac is blowing warm on driver’s side and cold on passenger’s side. I have never had the ac recharged or looked at by anyone. I typically do my own car maintenance and problem solving, but this one has me stumped. Could it be as easy as recharging the ac? Any ideas?

    • Mark Gittelman

      Jennifer: When the AC is cold on one side and not the other it indicates a problem with the temperature control system inside the car (climate control) specifically with the temperature door motor or control head. I recommend some dealership level diagnosis as they have a tool that interfaces with the system.

  65. Charlie

    Hi Mark, I have a 2007 Honda pilot. AC was not blowing cold air at all. Last summer I used a gauge set and recharged the system. It blew cold for a day and then was warm. I took it to Pep Boys the other day and they said the refrigerant was 5 oz low (10 months after I recharged it). They filled the system to proper charge, injected dye, and watched for an hour and could not detect any leaks. Cold air that day but by the next day it was tepid at best. Any thoughts before I change the expansion valve and evaporator? Does it just sound like a slow leak?

    • Mark Gittelman

      Charlie: It sounds like a 2nd opinion is in order. I would spend some time finding someone in your area with a proven track record at fixing complex AC problems before you start replacing parts.

  66. nick

    Mark, my question is my ac in my 2006 Toyota corolla blows cold air for maybe 2 min. then hot air could it be the thermostat. Or something else? I have not taken it in any where yet and I really don’t want to for money reasons. If it is the thermostat I can replace that and its probably a 20 dollar part. thanks Nick.

    • Mark Gittelman

      I don’t think it’s the thermostat Nick. If the thermostat was bad the car would overheat. Car AC is a complex system and your issue will most likely need professional level diagnosis.

  67. Jackie robertsin

    I have a 95 pathfinder. A/C gets ice cold then all of a sudden turns warn. I picked up a ex/ chill n checked it. Its full of coolant. The gauge said 45 so I didn’t put any in. Does anyone know what’s wrong with it?. At night it stays ice cold. But with temps being 90 here in Fl. In daytime it’s just blowing cool then warn.

    • Mark Gittelman

      Jackie: Unfortunately, car AC is a complex system and many things can cause this type of condition. With that said, I will throw out a few common issues to check. Evaporator freeze up caused by an expansion valve or orifice tube issue is one. 2) Moisture in the system can freeze causing a temporary blockage and cause this issue as well. Evacuation, holding a vacuum for 20 minutes to remove moisture and a recharge would eliminate this possibility. What’s wrong with your pathfinder? That will take expert diagnosis to resolve.

  68. scott

    Here is one that has me boggled. 06 Saturn Vue. Ice cold air at idle. Remains ice cold in neutral no matter the rpm even up to 3000+.(Manual transmission) Ice cold until you hit 30-35mph then looses all coolness. Come under 30mph no matter engine rpm and ice cold a/c?

    • Mark Gittelman

      Scott: We use to have that problem with the 80’s and 90’s firebird/camaro when the owner scrapped off the front air dam on a parking curb. Without the air dam the aerodynamics pulled the air away from the condenser at speeds above 30mph. Whats wrong with your car I have no idea, but come back and let us know so others can benefit.

  69. Alan

    A/C seems to go away temporally during accleration from a complete stop. Especially from a red light. Not blowing as hard as it use to.

  70. Toby

    I have a 2011 Versa. It would blow cold in the cooler temperatures, but on the hot days it would not blow cool. I took it to a Firestone place and they said I had a leak and fixed it with a “kit”. It worked for about a week, but has reverted to the same problem. Thermostat maybe? I read this page and will try to make sure radiator is not plugged with bugs, etc.

  71. Andrew K.

    Curious, I have a 2001 Ford Explorer Sport Trac. It blows cool, but not cold.. no matter the speed/rpm, idle/driving. When I turn the max a/c switch on, I hear a stead click from under the hood @ about 1.5-2 second intervals (sounds like its coming from the compressor). I am in South Florida, and the temps at this time get to be around 95-96 degrees, temp inside the cabin higher. It’s definitely blowing cool. Does the clicking have any tell-tale sign about the compressor or any specific part?

  72. Matthew

    I have a 2000 pt cruiser. The ac hasn’t blown cold air in over a year and when the ac is turned on the ac cycles on and off quickly. I bought a recharge kit to see if it would work. Here is my question. Once I put the recharge kit with the guage. As the motor cycles it goes from almost zero to almost in the red each times it cycles. Is the gauge supposed to stay in the green? Or go back down? And also one line is physically cold and the other the low line which the recharge goes into is warm but not hot. Thank you.

    • Mark Gittelman

      Matthew: It sounds like you have a major problem with this system. The gauge that comes with the recharge can are often poor quality and shouldn’t be used for diagnosis. Mechanics use a manifold set to get pressure readings from the low and high side at the same time for diagnosis.

  73. Constance

    I have a 1999 Jeep Grand Cherokee Laredo V6, and my AC blows really hot air but when I try to put refrigerant in it the smallest amount makes it read too much pressure. How do I know what’s clogged and how do I fix it?

  74. Owen

    Hello Mark, I have Mazda Protege 2000(1.8L). Recently my A/C stopped cooling . I have replaced compressor, with one I got on eBay (reman), new expansion valve, cleaned evaporator really well and placed a new dryer(new oil with UV stuff). Also new ac relay as the compressor would stay engaged at all the time and this car is designed to cycle. Vacuumed the system with rent a tool from Auto zone for 30 minutes, and tested for leaks keeping the vacuum for another 30 minutes. Filled the system up to a needed pressure, and confirmed the pressures with manifolds. High side supposed to be 190-240 and low side 22-42 according to manual. It shows now my low side is 42 and high side barely 190. I have also cheeked all the tubing around and got 122 F out of the compressor to condenser and dryer , after dryer its 75 degrees F, going in to expansion valve also 75, coming out of evaporator back to the compressor 59. The line that goes back to the compressor is cold to the touch.(~59F) Temperatures can be slightly of as used old school thermometer. Inside the car ac puts out 62 degrees when there is 105 outside and 50 when there is 85 outside. Any help or and ideas would really help as well as appreciated. Thank you in advance!

    • Mark Gittelman

      Owen : This is a tough one. The amount of total charge in the system is critical for output temperature, but with the pressure readings you supplied the charge appears to be very close to optimal. Personally, I would question the operation of the re-manufactured compressor as the readings are consistent with a worn compressor or a miss-calibrated expansion valve.

  75. Thomas

    Hi Mark, My daughter’s 1999 Camry LE had a new compressor replaced last September. the air blew cold for a while then last month the air is blown cool, not cold. My mechanic checked it out and it was a leak, reman compressor malfunction. However, it started to blow cool air again. The mechanic tested it and found no leak whatsoever, he suggests that I have the windows tinted to reduce the heat. However, I don’t think it’s that and the air is still not cold like my other cars’ AC. Please let me know what you think or what I should do. I really trust this mechanic and he has saved me lots of money and I don’t think he’s lying to me.

    • Mark Gittelman

      Thomas: I’ve seen to many remanufactured compressors fail to not think it could be an issue. However, diagnosis would begin with 2 things. High and low pressure readings and knowing the temperature of the air coming out of the center vent on low blower speed at its coldest.

  76. Thomas

    Hi Mark, I checked the vent temp when the AC is on in the morning and it reads 60. Later in the day when the outside temp is 95+ it reads 74. Talked to my mechanic and he said that it could be the condenser may need to be cleaned, the compressor is working properly and there’s no leak. What is your opinion?

  77. Scott

    Hi Mark, thanks in advance for taking the time to answer all our questions. I noticed today that my ac cools fine when driving slowly (less than freeway speeds), but starts to get warm and humid above 55mph. Low speeds but high engine RPM is not causing it. It happens whether I am on ‘recirculate’ or on outside air. Any ideas would be appreciated.

    • Mark Gittelman

      Scott: The symptoms you described are often related to issues with air flowing across the AC condenser mounted in front of the radiator. Weak or incorrect fan operation is one of the many possibilities. Clogged with bugs or debris an other. Also Jeep installs a short black air dam to divert more air, up and over the condenser. If this is damaged or missing it can allow the condenser to starve for air, and the faster you go the worse it gets. These are just Possibilities. If I was your technician I would first get some pressure readings both high and low and diagnose from there.

  78. Scott

    Thanks! I will clean the condenser and check the air dam / air flow, then I will go buy a manifold. Appreciate the tips!

  79. Dale

    Hello. I have a 2005 Chevy express van. Went to have the AC serviced today and was told it had a full charge and no leaks. This was at a jiffy lube so that’s as far as they can go with it, but was wondering if I could troubleshoot it. It blows warm air mostly, once and a while it will spit out some cool air but that doesn’t last. Can’t find the pressure switch. Any thoughts would be appreciated.

  80. Mike

    Hey I have a 2006 Mazda 3 S 2.3L and have to ask what might I check into for a/c temps, specifically if it’s say overcast and 80 or below it blows chilly from the vents, but if it’s god awful hot and during the day then I’m lucky if I can even feel cool at the vents. An acquaintance that runs an a/c shop arranged for my expansion valve to be replaced thinking that might be the cause of the issue. However, that did not solve the issue (it’s always been like this from the time I’ve had the car. Others with the same model swear that it can get cold when it’s hot out buy I’ve never seen it.

    • Mark Gittelman

      Mike: An Air conditioners capacity to cool under heavy loads when it’s brand new depends on how much freon it holds. A Mazda 3 doesn’t hold much. With that said you need to get more scientific with the issue and run an AC performance test on it when it’s cooling great and when it’s not. Then compare these results with the peeps that say you can do better.

  81. Mike

    A good point, the temperatures when as describe early morning/overcast and below 85 outside averaged mid 40 degrees at vent temp during height of day at vents even when letting run for extended period of time was averaging 68-72.

  82. Kayla Perry

    Hi Mark. We have a 2003 Ford Excursion 6.0 Diesel. We had the system evacuated they checked with a vacuum and it’s holding pressure just fine. We recharged it and it’s blowing but not blowing cold at all. Any ideas?

    • Mark Gittelman

      Kayla: The fact it holds a small vacuum doesn’t mean it will stand up to the high side pressure of over 250 PSI. With that said, any ac problem diagnosis starts with obtaining high and low side pressure readings with the compressor engaged.

  83. Dawn

    Hello Mark, I have a 2011 Chevy Equinox that has been blowing cool to cold sporadically. Today was the first day it most obvious though. The outside temp was 68 and my car ac setting was on 66 and I was not freezing, which usually I am. I could feel it blow cool then cold then cool. I called the dealer to ask about the extended warranty coverage and gave a description of what it is doing and was told they needed to see it when it is “acting up”. I can schedule an appointment and ask to have the high and low temps checked, but in general can you guide on what type of answer I should get next? I know that is a very broad question but many times feel that I will be taken advantage of because I really have no clue what I am dealing with or what I am talking about when it comes to cars. Any advice would be great. Dawn

  84. Luis Gonzalez

    Mark, I would first like to thank you for helping many people in the past. I am in a similar need and hope you can offer a bit of insight. I recently took my 2006 VW Passat to a shop which did a leak test on my ac system and there were none found. The pressure switch was replaced and they hooked it up to their machine which had pressure gauges on board. The low side bounced from around 65-70 and the high side maintained approximately 100 psi. The A/C starts to get cool but shortly after it comes out hot again. The shop is convinced that the compressor is shot. I’m just looking for a little more reassurance before I dump $500 on a new pump.

    I will add that my compressor appears to have an internal clutch as the outer pulley is always running no matter if the ac is switched on or off. Both of the fans in my fan pack spin and appear to work as required.

    Thanks in advance!


  85. Angela

    Thanks for taking the time to write this article Mark. I have been googling for hours and days, and haven’t been able to find an answer to my problem. All the typical issues have been weighed out of the equation. Maybe I’m not asking the right question in the right way or maybe the info just simply does not exist on the net. Maybe you can help me out? 98 Buick Le sabre LE. The A/C has not worked since the beginning of summer last year. Someone put more refrigerant in it, but it did nothing to help. Air blows through the vent, but it’s not getting cold.

    So far, I’ve: Checked the relay for continuity (had continuity), Checked the pressure to see if it might be leaking (it was actually overfilled, so I released some pressure), Checked the condenser fan (it’s working), Checked the clutch/compressor (it comes on fine), Checked the condenser for clogs (there was very little), Check for cabin filter (could not find one, other than the plastic grid/screen that would hypothetically be covering it), And like I said before, refrigerant has been added to the system since last year. The thing I’ve noticed is that the accumulator is not getting cold at all. There was condensation on the accumulator and it was getting cold when the air conditioner started not working last year. But none at all now.

    Also, I’m not sure if this applies, but the other issue I’ve had with the ventilation system is that the air only blows at the window vent. It won’t blow anywhere else. I’ve also had an issue in the winter where my heat would only work intermittently. It would sometimes blow hot, and other times cold. Therefore the only conclusion I can come to is that the accumulator may be bad, or something with the electrical wiring or the electrical control panel.. or both. I’m not sure. This is where you would come in, if you would be so kind to help me out. What would you suggest in my situation?

    • Mark Gittelman

      Angela Said : “This is where you would come in, if you would be so kind to help me out. What would you suggest in my situation?” When an AC system is inoperative for years, damage is usually far reaching. The giant list of possible causes can’t be addressed in the comment section of a blog post. Especially if this Buick has dual Zone Climate control. However, the first step in logical diagnosis is obtaining pressure readings at the high and low side test ports.

  86. scott

    My 97 Chevy silverado is cool at start up and staying engaged but it is not cooling very well only a couple minutes after start up have to turn the fan speed way down to even notice a little cooling. It has a new compressor new condenser and new evaporator . The low side is reading 70 and the high side reads 250 and climbs up to 300 at times your help would be very much appreciated.

    • Mark Gittelman

      Scott: I would have replaced the receiver dryer and orifice tube along with the parts you listed. The low side pressure is certainly too high. Unfortunately, a bunch of things can cause the readings you got. Over charge is the most common as freon level is critical, moisture in the system and blockages are a couple more.

  87. Sophie

    I have 1990 Buick Century, in 2014 a car shop convert a new car A/C system. This year the A/C is not working. A car shop recharged freon and put dye to check that no leak, total 5 different times. Each time the cool air only last for 3 days. then the shop replaced a new compressor. The air conditioner still last for 3 days only. What can be wrong? Please advise. Thanks.

  88. Sophie

    I paid for the shop to put dye and check for leak but the shop never can find it ( 5 times). Instead, installed another new compressor that was installed new from last year by other shop. Where could I suggest the shop to look for the medium sized leak? Thank you, Mark.

    • Mark Gittelman

      Sophie: My thought is the shop shouldn’t need our help to find a leak of this size. With that said, there are a couple of spots that a puddle of leak tracing dye would be hard to see. One is a leak around the evaporator since it’s enclosed in the heater case. Condenser leaks are also hard to see because direct view is blocked. However, any mechanic with a small amount of experience already knows this.

  89. Sophie

    Dear Mark: You are such an honest great mechanic who gave me your valuable advise. I shall bring the information to that shop for their A/C mechanic to hopefully fix my car A/C once for all , and no more hassle to me and them. I think I have wasted too much money on such a thing, but learned a big lesson. Where can I find your shop in Kitsap County? Best wishes to you and your business! God Bless! Sophie 🙂

  90. DAN

    Nissan Sentra 96, replaced evaporator, expansion valve, dryer filter, hi pressure switch and reman compressor. Vacuum system and recharged 134 a, low side 30 psi, high side 225 psi, air temp coming out the vent 65. If I add more freon warmer air coming out. Clutch working continuously not like on my 2012 Honda crv, Before I changed all these parts I had it in a shop where they put dye into the system. I can still see green color coming out when I disconnect hoses. Maybe clogged with dye?

  91. Tony Zampini

    Hi, Quick question. How can you tell how much oil is in a system? It seems like you would need to know this in order to determine how much to add.Thanks.Tony

    • Mark Gittelman

      Tony: Good question. Unfortunately, there’s no easy answer.The only way to know how much refrigerant oil is in the system is to drain and measure it. Even this is not that accurate. Most of the oil collects in the compressor sump and the receiver dryer. However an ounce or 2 can hide in the condenser and throughout the rest of the system.

  92. Sophie

    Hi, I brought my car back to the shop and showed the spots you hinted to the owner. The shop checked and replaced a hose, kept my car for a week.
    I still have the one day air conditioner only after I got my car back. I am so frustrated. How can I do from this point? Please help me. Thank you very much. Sophie

    • Mark Gittelman

      Sophie: As you know you can lead a horse to water, but you can’t make them drink. AC leaks can be difficult to solve. If your shop doesn’t have the skills, then it’s time for a 2nd or 3rd opinion. Not always, but often the most skilled mechanics work at the dealership. They should at least be knowledgeable of what to look for on your specific model as they specialize in the brand.

  93. Sophie

    Hi, Mark? Does that means the money the shop charged me has gone down the drain? The compressor was new from last year by other shop, this time this shop couldn’t find a leak then replaced another compressor which didn’t help but waited my money. Can “the shop” at least pay for other shop to take care of the leak if other shop can easily fixed that “the shop” should be able to fix it? Some how to compensate my cost?

    • Mark Gittelman

      Sophie: I can’t answer that question. If I was this shop I would be embarrassed by my incompetence and try to help. Weather they will render assistance for wasted money on a problem still not resolved is a question to ask them.

  94. Sean

    I have just bought a 2007 Honda Civic EX. The AC didn’t seem to be working too well, so I went to charge it (using a can of Freon and charger that came with it). I connected the gauge/charger to the low side (only side it would connect to) and it showed the system was over charged (almost in the red). So I let some freon out (which seemed to be VERY oily – but I have never dealt with freon before so I am not sure). I then tested the system again, it while it was 85 degrees outside, it didn’t seem to blow COLD, just a bit better than cool (on MAX, recirculate). Just now (at 8pm) after reading this page, I put a thermometer in the driver side center vent and it registered 53 degrees. I know the previous owner had added freon last year, and I changed the cabin filter 2 days ago. when on low, it seems to be blowing cold, but when cranked up 2/3 air flow or better, it does not seem cold at all. Any suggestions on what to check? Thank you in advance. I hope I provided enough information. Sean

    • Mark Gittelman

      Sean: The amount of refrigerant installed is one of the most critical factors in how well the system cools and also diagnosing problems. The system should be recovered, evacuated for 20 minutes and recharged with the exact amount of freon required. This specification is usually near the charging port or on the receiver dryer. That’s where you need to start because you don’t know whats in there or how much.

  95. Molly

    Hi Mark. I see this article is old and hope you see this, but I couldn’t find another way to message you. I recently bought a 2001 Chevy Express 1500 handicap van to transport my disabled 3 year old in his wheelchair. Now that we are hitting 80 degree days I found out the a/c is not working right. It blows hot/warm air unless I am traveling at highway speeds 65-70+. The Max a/c setting doesn’t work hardly at all and seems to have less pressure behind the air than the normal setting does. I can’t afford to take it in and pay out the behind just to have them tell me what’s wrong. What would you suggest I have looked into first? Thank you for your time. Molly

    • Mark Gittelman

      Hello Molly: I wish I had a simple answer for you, but car AC systems require expert hands on diagnosis for problems such as yours. If I was there the first thing I would do is connect a set of manifold gauges and get some pressure readings. With that information it’s then possible to proceed down a path of logical diagnosis. Here is a more recent article I wrote on the subject entitled What is wrong with my automotive AC system. If you get pressure readings come back here and reply to this comment and I’ll try to help you.

  96. Janelle

    Hi Mark I just recently replaced compressor and dryer on a 05 ford Taurus I vacuumed the system no leaks so I attempted the recharge. Now what I mean about attempted is when i hooked up the gauge it read zero as it should so start to add first can 12oz car takes 34oz as I add finally hear compressor kick on, but as I get to end of first can gauge reads that system is now full. Makes no sense even hooked up a different gauge and it read same thing, but there’s only 12oz in whole system. Please any input would be greatly appreciated.

  97. Dave

    I have been working on a 1994 Chrysler Lebaron convertible, 3.0L. all a/c components have been replaced. Condenser, evaporator, receiver/ drier, expansion valve, compressor and all hoses. On a 95 degree day, it will blow 60 – 63 degrees, but does not get colder driving down the road. Electric fan is functioning properly, a/c pressures are approximately 250/25-30. Trickling water over the condenser or putting a box fan in front of it makes no difference. i have double and triple checked charge amount. New oil was added to specification according to reputable repair guide(Mitchell on demand). I have swapped out the expansion valve and receiver drier since installing parts and there has been no change. I know there is a lot of heat in vehicle because of convertible top and non-tinted windows. The compressor is not cycling abnormally,and the idling temperature split from ambient temperature to center vent is within spec, about 30 degrees. I work at a shop and used professional equipment to do the vacuuming and charging, I am a mechanic and do some a/c repairs, about 6 years experience since starting a/c work. Any suggestions?

    • Mark Gittelman

      Dave: These old Chrysler systems are troublesome. As you know its hard to make a judgement call on such a complex issue without being there. However, I will mention that I had an old Chrysler with perfect pressures that wouldn’t cool properly. The foam seal on the temperature door that sealed off the heater core had rotted away and allowed warm air to flow over the evaporator all the time. Since this was a south Florida car we sealed the heater door closed permanently and the air cooled nicely.

  98. John

    Hi Mark. Thank you in advance for your help. I have a 2013 BMW 335i and the A/C takes a long time to cool and never gets cold. My mechanic has tried his best but can’t make it any better. The system has the correct charge and the pressures are supposedly normal. Yet all other BMWs I drive or ride in get cool quick and are much colder 10-15F. About a year ago the system was low but the leak could not be found. So far replaced: expansion valve, aux fan and Evaporator temp sensor. Any ideas? Thanks, John

    • Mark Gittelman

      John: I would really have to see the pressures at idle and 2,000 rpm to form an opinion. However, if what you say is true, and the pressures are perfect then my attention would turn to the temperature door adjustment and the climate control system that controls it.

  99. Todd

    2011 Ford Escape: Car is blowing ICE and getting a mist and not cooling like it should this happened 6/2016 on way back from Tennessee back to Texas. 7/2015 – replaced Compressor Clutch/cycling switch & Transducer pressure switch. 3/2016 replaced Condenser. Dropped off at PepBoys from 6/26/16-6/29/16 and they could find nothing wrong and system was fully charged and could not find any leaks. Need help on getting this fixed.

    • Mark Gittelman

      Todd: The most common cause of ice and mist discharged from the vents is evaporator freeze up. The evaporator should never freeze and it actually reduces output temperature. It’s the job of the expansion valve to stop this from happening. Therefore this part would be at the top of my list for diagnosis.

  100. Andrae Freeman

    Hey Mark, I have a 1971 Oldsmobile Cutlass. I’ve replaced the compressor, expansion valve, replaced the POA valve with the bypass valve. The evaporator and condenser are the same for the r12 system. Everything else is r134. The system works. It comes on, the hoses and pipes under the hood get real cold and condensate. But the temperature in the cabin don’t feel like the pipes. The air coming out the vents is cool but not cold. Now I have a shut off valve on my heater hose not allowing water to pass through my heater core, but I still feel heat from somewhere even I drive without the ac on, but the heat is on my legs and feet not through the vents. Any ideas??? Thanks

    • Mark Gittelman

      Andrae: There is many layers to diagnosing a complex problem such as yours. I usually start with high and low pressure readings at idle and 2,000 rpm’s to make sure the system is being all it can be. However, with your symptoms I would check the physical temperature of the evaporator and take a look at the temperature door condition and operation. On a 45 year old car it’s likely the factory installed foam seal is either gone or not sealing the door properly.

  101. Richard

    Mark, I have an interesting problem. I just replaced the compressor, expansion valve and drier on a 1990 Mazda Miata and converted the system from R-12 to 134a. The system was properly evacuated, and held at vacuum for 45 minutes, then filled with 23 oz of 134a. I replaced the PAG oil in the compressor with 4 oz of ester cool oil and added 2 oz to the drier as instructed by the compressor manufacturer. System pressures after charging the system were mid 40 psi low side and around 250 psi on the high side. In the morning with the ambient temperature around 70 or 75 deg F the vent temp inside the car will be in the 30-35 deg F range. By mid day with the ambient temperature between 85 and 95 deg F I can only get a vent temperature of around 60 and only after about 20 min of driving will the car read below 60 on the thermometer. The expansion valve is also whistling now when it didn’t before. Since I am used to having 40 to 45 deg F air using R-12 on hot days, I am very disappointed with the current system performance.. I am at a loss here. Do I have a bad expansion valve and should I convert the system back to R-12?

    • Mark Gittelman

      Richard: You didn’t mention the miles, but since it’s a 27 year old car I’ll just guess it’s high. Diagnosing old, high mileage systems is difficult because of all the variables involved. The condition of the heat exchange fins (condensor, evaporator) and the temp door foam seals are common issues on high mile cars. With that said, it’s not uncommon to have system performance complaints after conversions.

  102. Vernon

    I attempted to recharge my ac , I had my wife turn the car on and asked her to turn the ac and fan on high will I opened the hood and connected the recharge hose of ac pro. When I asked my wife if it was getting cooler she said no it’s hotter. when I looked in the car I noticed she had the heater on high. I switched it to ac buts it’s still not cool. Did I cause any damage to my ac system?

    • Mark Gittelman

      Vernon: Having the heat on high wouldn’t hurt the system, but adding freon to an already full system could. I would start with a basic diagnostic and get some pressure readings to see what’s wrong with it.

  103. Tim Taylor

    Hey Mark, I bought my wife a 2009 Dodge Journey with less than 40k miles on it. After about 2000 miles of driving, we starting hearing a clicking/knocking sound from under the dash that originally sounded like it came from under the car. As of a week ago, the a/c stopped blowing but will still get real cold when driving down the road with it turned on. The clicking remains and is intensified the higher the a/c is turned up. I have seen that this was a common recall with the Dodge Rams for the blend door. What would you recommend I do? Thanks for your help and time.

    • Mark Gittelman

      Tim: It does sound like a door motor problem. The dealer is the place to go for these repairs. Their diagnostic equipment can quickly interface with the climate control system to diagnose issues and calibrate replacement parts. If it turns out to be a known problem, you can call Dodge customer assistance and see if they will help out with repairs. Sometimes they pay for parts In the interest of customer retention. They help people after the warranty expires if they think they’ll buy another Dodge.

  104. John

    Hey Mark: I asked you a few weeks ago about my A/C taking a long time to cool and never gets “cold”. Again BMW says “it’s working as designed”. I am miserable in this car in the FL heat. At idle the low pressure is 35 and high is 205. At 2,000 rpm LP IS 25 and HP 245. Any advice? Thank you for your time. John

    • Mark Gittelman

      John: There is a large differential in pressure between the readings supplied at idle and 2,000 rpms. This is an indication of either an incorrect level of charge or a worn compressor. However, at 2 grand this ac should be cooling nicely according to the readings. So now I’m wondering the miles on the car and the actual output temperature from the center duct with the blower fan on low 2. It could still be a temp door issue as I mentioned last time.

  105. Steve

    Hello Mark, I have a 2012 Ford Escape and the air conditioning is acting up. When it is really hot out it blows warm unless I’m on the highway. It works fine at high speeds. When I am driving around town it usually never works. When it rains it works. When I spray off the radiator with a power washer it will work for a half hour or so.

    • Mark Gittelman

      Steve: Although your issue will take some diagnosis the most common cause of your symptoms is lack of air flow across the condenser. This is explained in the article above and discussed by Pat Goss in the video as well.

  106. Adrian

    Hello Mark , I own a 1996 Chevy Tahoe sport 2dr 4wd , A few days ago I had a AC system leak repaired (schrader valve). Vac/ recharge was done, but now it takes at least 15- 20 min for system to cool and during heat of the day it never really seems to cool the truck cab down to a comfortable level because after 15-20 mins even though you can all of a sudden feel the air get cooler, but I’m usually at my destination then. I’ve cleaned the evaporator under the dash twice and condenser in front of the radiator, still the same issue. I’ve checked engine coolant, air flow / blend door servo motors work, but (slightly noisy) and I did notice a small amount of cool air coming from top of dash (defrost vent area) even though air flow direction is switched to dash vents only. I also noticed that fresh air / recirculate door only opens when system is set to defrost,otherwise the fresh air door closes when you switch the system to anything other than defrost and only recirculates air in the truck cab. The selector on ac control panel will not operate the door. Compressor seems to work, clutches engage and spins with the belts, freon levels seem to be okay although I checked with 2 different cheap gauges.

    • Mark Gittelman

      Adrian: As you mentioned, the door servo motors are a known problem on your year and model Chevy. I wrote an article about the AC airflow problems on these trucks. And an updated article about GM temperature door problems. With that said, the list of possible causes of your symptoms is huge. If this was my truck I would start by taking high and low pressure readings at idle and 2,000 RPMs. With this information I would at least know what direction to take further diagnosis in.

  107. Monica

    Mark, I could really use some help! I have been reading your blog and trying to educate myself. My 2014 Ford Explorer with 28,000 miles has had an AC issue that the dealer continues to deny even exist. I live in Texas and the heat is brutal over the summer. After my 1st visit, they claimed pressures are within normal range and the vent output air is 42 degrees. A week later, I took it back because it didn’t work as they stated. I asked the service manager to duplicate a reading of 42 degrees on the center output air and they were unable to get the temp below 65 degrees after 30 minutes when at idle in my presence. I left with the understanding that there was a problem that needed to be fixed and after 1 week they called again and reported “no need for repair” that output air is 42 degrees and pressures were normal. He reported that they drained the Freon to measure the amount and replaced it, confirming no leak. What could I say and do to ensure my AC getting properly repaired and I am not getting pushed around.

    • Mark Gittelman

      Monica: Obviously there are no easy answers to fixing your problem. However If I was in your shoes I would call customer service and open up a case file. Hopefully you saved all of the dealer service department receipts to document your unresolved concerns. In many cases Ford can get involved and work with you to resolve this tough issue.

  108. Jennifer

    Hi mark, I have a Nissan 1995 200 SE-R. My car AC system isn’t blowing cold air. My mechanic refill r134a freon with lube air into my car for $100. But only one day later, the system wouldn’t blow cold air anymore. I went back there, he refill it again and told me no leak when he checked by eyes. The cold air was only for one day again. The third times, I left my car there for him to check, then he told me the fluorescent dye he used to test did not show any leak mark at all. He said the problem is on my condenser (he estimates to fix it will be parts $240 plus $100 labor). My question is the system only keep blow cold air one day each time right after he refilled freon, is it possible has no any leaking at all? Is the problem on condenser? Thanks.

    • Mark Gittelman

      Jennifer: The older the car the more likely it is to have a leak. The fact that it lasts only 1 day probably means that it has a large one. As for whats wrong with your car I can’t guess, because the list would be massive. In this giant list of possibilities the condenser would be in there. I wrote a great article about how to find AC freon leaks. Give it a read.

  109. Alex

    I recently had an issue with my AC system. It just stopped working so I decided to check and see what was going on. I took it to a shop they they told me it needed a new compressor and expansion valve. I changed the valve myself and started to fill the refrigerant back to spec. At spec 32 Lo 250 high it still blows warm and I hear hissing in the cabin. Added little by little and it started to improve. Finally got it blowing cold but I checked with my gauges and see now the lo side is 40-45 and high is 325-350 ambient temp was about 90 degrees. Is the compressor really no good? What would be the explanation of the system working with higher levels? Condenser and expansion valve are new. I hope the compressor is not really the issue.

    • Mark Gittelman

      Alex: You didn’t mention the year, make, model or mileage. But a repaired AC system is evacuated and refilled by the weight specification not pressures. The total charge is listed on an under hood label. If the compressor is not noisy and can produce pressure above 300 psi I doubt it’s defective. The accuracy of some gauges can also be a problem when the system works and the readings are off.

  110. Sharon

    I have a 2010 Honda Odyssey with about 131,000 miles on it. The A/C is suddenly blowing cool only at idle or low speeds. I checked to see if the fan runs when the A/C is turned on, it does. The A/C blows strong. I also reved the car to over 2000 rpms while in park and it gets cold. It blows cold at 30-40 mph+ What could the potential problems be? I don’t want to invest a lot of money into the car with this mileage and the winter coming. We have never changed the cabin filter, could this really be a cause?

    • Mark Gittelman

      Hi Sharon: As mentioned in the article diagnosis must begin with getting pressure readings on both the high side and low side while the AC is running. There are just too many possibility’s to start guessing without that information.

  111. Chris

    Hello Mark, Very useful blog you have here. I went through it, but unfortunately my car ac problem seems very unique in my Infiniti G37. My ac cools ice cold when car is idling and at all speeds below 60mph. Once you get up to 80mph the vent air temperature rises from around 40 degrees F to about 65 F. Happens in auto mode as well as manual mode with re-circulation on and fan at high speed with the lowest temp setting on ac. The high and low side pressures are within what is specified in the factory service manual. Compressor and clutch as well as the drier has been changed with brand new parts and gas refilled. When the vent air temperature increases the compressor is still working, but just cooling output is reduced. What could be the problem? There is a refrigerant pressure sensor on top of condenser, could it be that? Radiator, condenser are all clean and damage free. Car is only 2 yrs old with very low mileage.

    • Mark Gittelman

      Chris, your symptoms are an exact question on the ASE car air conditioning certification test. The answer on the test is the car is missing an air dam that diverts air at higher speeds across the ac condenser. Without the air dam a vacuum is created pulling air away from the condenser at speeds over 50mph. As for your car, you didn’t mention the miles or why they replaced the compressor and other parts. Once you start replacing parts other variables get injected into an already complex situation. Did they follow procedures or take short cuts?

  112. Chris

    Thanks for the fast reply. I took a look at the factory service manual and part diagrams online, i don’t see any specific part that looks like an air dam besides the one in the picture link below. (under the condenser, the long flap which i checked and i still have it on my car) Besides the air dam, what could be other things i could troubleshoot? There is an ac refrigerant pressure sensor on top of the condenser, could it be faulty? or something inside the evaporator? Compressor was changed cause the technician found a leak inside the compressor seal, i am guessing the leak was very small as before and after replacement of compressor the original problem still remains. car has done 22k miles, 2013 model.

    • Mark Gittelman

      Chris: The problem with me providing advice on replacing parts is 2 fold. If the car is under warranty and the highly trained dealer techs can’t figure it out then I would say may chances of coming up with something they haven’t checked are slim. Second, in order to proceed in a logical fashion I would need to read the pressures on the high and low side at the time of the fault. Hypothetically, this would mean having a set of gauges connected and laying on the windshield while your traveling 80 mph.

  113. Chris

    Thanks Mark, il get you the high and low side pressures as soon as I can find a ac diagnostic kit with long enough hoses to come from engine bay and into the car so it can be safely used while driving 80mph. Might take a few weeks. Unfortunately dealer “qualified” techs have no clue and their suggestion is to replace everything in the system with new parts hahaha.

  114. Erick

    Hi, I have a Toyota Tercel 95 with 167,000 mileage. My problem is: The Air Conditioning in venting very low in the passenger side vents. The car throws pretty good amount of air but not that cold you know. I recently refill it with 134a. It might drop a few degrees, but still not that cold. When I accelerate the car usually starts to throw more air and colder, but still not that cold. What should I do based on my car specs and problems.

    • Mark Gittelman

      Erik: Diagnosis should begin with taking low and high side pressure readings at Idle and at 2000 rpm’s. With the age and miles on the vehicle and not knowing what parts are original I can’t hazard a guess at the problem without hands on diagnosis.

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