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!

Remember when your car has been baking in the sun heat is stored up in large quantities and must be removed before it starts to feel cool inside. But what if the air does not seem to get cold after 5 minutes?

There are many factors involved that affect the actual output temperature at the dash AC vents. To follow will be a few examples of common problems that I find when inspecting a car air conditioning system that is 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. 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 their system on their own they will 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 that is common in my area at this time of the year is a radiator or a condenser that has been 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.

Make sure the recirculation 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. And Mr Goss is for sure right that putting to 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.

70 thoughts on “Car AC Not Blowing Cold Enough

  1. Mark Gittelman Post author

    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.

  2. 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.

  3. Mark Gittelman Post author

    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.

  4. 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.

  5. Mark Gittelman Post author

    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.

  6. Mark Gittelman Post author

    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.

  7. 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.

  8. 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.

  9. Mark Gittelman Post author

    Thanks Eraldo: The best place to start is to connect a set of gauges and get some pressure readings for the low and high sides. This gets you heading in the right direction.

  10. Mark Gittelman Post author

    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.

  11. 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?

  12. 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.

  13. Mark Gittelman Post author

    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.

  14. 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?

  15. 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 :(

  16. Mark Gittelman Post author

    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.

  17. 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.

  18. Mark Gittelman Post author

    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.

  19. 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?

  20. Mark Gittelman Post author

    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.

  21. 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

  22. Mark Gittelman Post author

    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.

  23. 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

  24. Mark Post author

    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.

  25. 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.

  26. Mark Post author

    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.

  27. 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

  28. Mark Post author

    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.

  29. 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.

  30. Mark Post author

    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.

  31. 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!

  32. Mark Post author

    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.

  33. 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.

  34. 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

  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. 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!

  37. Mark Post author

    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.

  38. 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?

  39. Mark Post author

    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.

  40. 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.

  41. Mark Post author

    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.

  42. 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!

  43. 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?

  44. Mark Post author

    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.

  45. 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?

  46. Mark Post author

    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 http://www.youfixcars.com Note the video starts after a 15 second commercial. It’s worth watching. Here is the link http://www.youfixcars.com/rip-off-car-AC-repairs.html

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

  47. 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.

  48. 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!

  49. Mark Post author

    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.

  50. 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?

  51. 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.

  52. Mark Post author

    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.

  53. Roman

    Mark,
    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.
    Thanks,
    Roman

  54. 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.

  55. 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!

  56. 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.

  57. 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

  58. 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..

  59. Mark Post author

    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.

  60. 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.

  61. Mark Post author

    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.

  62. Mark Post author

    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.

  63. 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?

  64. Aaron

    Mark,
    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.

  65. Mark Post author

    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.

  66. 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.

  67. arif

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

  68. 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.

  69. 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?

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