Why is My Car Air Conditioner Blowing Hot Air and How to Fix It?

Have you experienced that your car air conditioner blowing hot air instead of cold air? Are you worried that your car AC not working properly again? Are you feeling annoyed because your car AC not blowing cold air, and you want to fix it as quickly as possible? If the answer to all the above questions is yes, then you are on the right page!

And I am saying this because, in this comprehensive guide, we are going to answer some of the most searched questions on the web; why is my car air conditioner not blowing cold air, and how to make air conditioner colder in car.

car air conditioner blowing hot air
(Disclosure: This post contains affiliate links and images. I earn advertising/referral fees if you make a purchase by clicking them. There is no extra cost to you. See our full disclosure here. )

The car AC is a machine, and like all other machines, it can also become faulty or show signs of defects.

And as the car air conditioning system components are not similar to the random home air conditioners, it is not always possible to detect where exactly the problem lies or what to do when you face defective issues.

And certainly, sitting inside a steel box (the car body) with zero air circulation plus hot air coming out on a summer evening is not going to make you happy or healthy either.

So, it is essential to know how air conditioning works in a car and what to do if it starts blowing hot air instead of cold air. It must be every car owner’s priority (if they are regular users of the cooling system.)

Hopefully, this detailed guide will help you find all the answers to these essential questions and help you learn how to fix a car air conditioner blowing hot air instead of cold air. So, just keep reading till the end to know every possible solution.

How Does Car Air Conditioning Work?

Before you jump to knowing what is the reason behind the car AC blowing hot air and how to fix it, you must know the car air conditioning components that cause the heck in the first place. Of course, it doesn’t change from manufacturer to manufacturer, but yes, you can get some modified versions in the newest model as compared to the old ones.

So, how does car air conditioning work? We will get to know that, but before, let us see the components that a car AC comprises!

A car AC has:

  • A compressor
  • An evaporator
  • A condenser
  • A receiver, accumulator, or drier
  • An orifice tube or expansion

These are the standard components of most automotive air conditioning systems available in cars today. Now let us see how the car AC works in general. The car AC is pressurized by the refrigerant, a type of gas that is present in the air condition system in all cars.

Usually, it is 3-4 pounds, but its quantity depends on the type of vehicle you are using. Then comes the compressors’ work; it compresses the refrigerant gas to liquid by compressing, and then it is cycled throughout the refrigerant line.

The next car air conditioner parts and functions include the work of the condenser. The refrigerant passes through a radiator-like grid, and the gas that passes through the condenser helps in removing the heat from the refrigerant.

After this process, the refinery moves to the orifice tube or expansion valve, and the tube restriction reduces the pressure and converts the refrigerant into a gaseous state again from the fluid state.

The next step is carried out in the receiver drier, where the moisture present in the refrigerant is removed, and then the refrigerant is passed on to the evaporator in the gaseous form when the heat is removed, and the refrigerant becomes cooler.

Are you still wondering, how does air conditioner work in a car? Check out this detailed video:

This is the working principle of the car air conditioning system in most passenger vehicles these days. If and when a glitch in any of these parts is detected, the air conditioner might not work properly and thereby start blowing warmer air comparatively.

You might also like: Why is My Car Heater Blowing Cold Air and How to Fix It?

Why is My Car Air Conditioner Blowing Hot Air? [Top 8 Reasons]

If you are experiencing your car air conditioner blowing hot air of late, then you might also be eager to know the reasons behind it, right? Well, every time, the reason might not be the same behind such hot air coming out from the car’s cooling system.

There are multiple reasons why the car AC blows hot air, and some of the most prominent ones are mentioned below. Have a look at these possible causes of why your car air conditioner not blowing cold air after a while:

There is a Refrigerant Leak

One of the prominent reasons your car is not blowing cold air might be a refrigerant leak. The refrigerant is the most significant component of the car AC system that ensures the AC blows cold air instead of hot. Thus, when there is a refrigerant leak in the car cooling system, it is a possible reason behind the car AC blowing hot air.

There would not be enough refrigerant present in the cooling system when there is a leak, which will not facilitate the cooling process to take place effectively. But even though it is a prominent reason behind warm air coming out of the car AC, it is tough to be detected by the regular car owners.

So, how to fix car AC blowing hot air due to refrigerant leakage if you cannot detect it in the first place?

Of course, the most effective solution is to take the car to an automobile professional so that they can detect the leakage using special UV detectors because the refrigerant gas has the property to become invisible when it leaves the cooling system. When they find the leakage using the UV detectors, they would be able to fix it easily.

The Condenser is Blocked or Clogged or Broken

If your car blows hot air when AC is on, then you might check for all the justifiable reasons behind such an issue. One of the prominent reasons for car AC blowing hot air instead of cold is a clogged or broken condenser.

In most cars, you will find the condenser located near the grille on the front side so that it can use the airflow to cool down the refrigerant when the car is driven. Thus, if a certain amount of debris or dust particles blocks the path of the condenser, there is a possibility that it might deteriorate the cooling property of the car AC, leading to the blowing of hot air.

Unlike the detection of refrigerant leakage in the car cooling system, it is pretty easy for anybody to detect the clogged condenser.

And it is easier to get rid of the debris as well. You can do it yourself, or if, in any case, you feel you cannot remove the debris, you can take it to a car mechanic who will do the needful at a minimal cost.

After the debris or dirt is removed, you must also check for any possible damages caused to the condenser due to such blockages so that it can be repaired as well.

Problems with the Electrical System

If you notice that the car AC blowing out hot air, then there might be a problem with the air conditioner’s electrical system. The electrical system is responsible for circulating the refrigerant throughout the cooling system, which ensures that the car AC blows cold air instead of hot.

And so, if you find out that the car electrical system is not working well, you might better consider it as a reason behind your car AC blowing hot air or not working properly.

There are several different electrical parts that operate the entire AC system, and one minor damage can lead to shutting down of the entire system so that any kind of shot circuit or misfire issue can be prevented.

But it is not always that you can detect electrical system issues by yourself. So, it is advised that if you do not find any other valid reason to blame for the car AC blowing out hot air, consider taking the car to a mechanic to check the electrical issues.

They can’t only detect the problem but will evidently take turns in solving it too! The cost of the repair depends upon the extent of the problem.

Bad or Broken Compressor

The compressor is considered “the heart” of the car AC, and thus, if it stops working, you know what can happen! The work of the compressor is circulating the refrigerant throughout the cooling system. So, if you want to fix a car air conditioner blowing hot air instead of cold air, you ought to look out for a faulty compressor.

When the compressor of the car AC does not function properly, the chances are high that the cooling system will not be able to produce cold air as the anti-freeze in the system would not be able to reach the AC condenser for cooling, thereby producing warm air.

Most commonly, the issues in the compressor arise when it is kept unused for a more extended period. And this happens mostly during winters when the car is non-functional.

This is the prime reason why most automobile manufacturers are heading to keeping the condenser active for a year by activating it through the defrost setting. Nevertheless, if you do not own any such latest car model, do not be disheartened; take your car to a mechanic so that the exact problem can be detected and solved quickly.

Clogged or Dirty Cabin Air Filter

If you notice the car AC stops blowing cold air after a while of having the runtime, you may well think there is a problem in the cabin air filter of the cooling system.

Though it is not always that all cars have cabin air filters but the ones that possess them needs to know that when the cabin air filter is clogged or dirty, it can block the pathway of the cold air throughout the cooling system, leading to blowing of air from the car AC.

The main purpose of the cabin air filter is to purify the air and let it pass through the cooling system without any obstructions. But when the filter itself is filled with debris, dust particles, bugs, leaves, and dirt of other types, you cannot expect it to function properly.

So, you need to keep in mind that the cabin air filter must not be dirty or clogged. And for that, you have to constantly keep cleaning it after every ride or once in a week or so.

If the filter is not kept clean regularly and the debris remains stuck in it, not only will it lead to the blowing of hot air from the system, but in the long run, it will affect the entire cooling system negatively.

Broken or Faulty Cooling Fans

Is your car AC suddenly blowing hot air instead of cold? Are you feeling the heat even when you are inside the AC car? If you are facing these situations of late, you must know that it’s the cooling fans that are causing trouble to your car’s cooling system.

When the cooling fans are broken or faulty, you will experience warmer air even though the AC is running at a low temperature.

The cooling fan has the simple purpose of cooling down the hot air in the AC condenser. And when the fan itself is faulty or broken, it would not facilitate cooling of the air inside the cooling system, which will lead to producing warmer air than usual.

Generally, when this happens, a visual inspection of the cooling fan can make you understand what kind of damage has been caused to the fan. If at all you are not able to detect the problem, it is advised you take the car to a mechanic to let him detect the issue and fix it.

Also, keep in mind that damages to the cooling fan occur when debris hits it while driving, so drive cautiously.

The AC Compressor Clutch is Bad

If you notice that the car air conditioner blows hot air sometimes, then look out for faults at the most coveted parts of the cooling system. The AC compressor clutch is one such part that ensures the AC blows cold air throughout. And so, minor damage in the compressor clutch may lead to the AC not functioning properly and blowing hot air instead of cold.

The function of the AC compressor clutch is to drive the compressor efficiently so that it can circulate the cold air throughout the cooling system.

If and when the compressor clutch becomes faulty, it wears down the functioning of the compressor much quicker than usual. And if you keep driving with a bad compressor clutch, it will more likely result in further damages that can make the repair costly too!

Not only does the faulty compressor clutch make the car AC compressor unworthy of any work, but it can also wreak havoc on the serpentine belt in the car and degrade its working capabilities as well. Thus, it is advised that you change the faulty compressor clutch as soon as possible to avoid extra damages and to lower the repairing cost also.

The AC Expansion Valve is Faulty

Are you still wondering why is my car air conditioner blowing hot air instead of cold air? Well, if you have been lucky enough not to encounter any of the reasons mentioned earlier, then lastly, you can check for a faulty expansion valve.

If the AC expansion valve does not run correctly, it can also lead to the entire cooling system failing impromptu, which might lead to the production of warm air from the AC or even lead to no-air production.

When the AC expansion valve doesn’t stick open or become faulty, it will force the AC compressor to pump out the refrigerant through the car’s AC system. Even though this condition is entirely undesirable, one cannot have control over it because of the faulty expansion valve.

And when this happens, additional pressure will be created on the AC compressor and other related AC components that will eventually lead to premature failure of the car cooling system. Thus, it is advised that if you find out that the expansion valve of the car AC is not working properly, try fixing it immediately by talking to a car mechanic.

You might also like to see: 13 Best Portable AC for Cars and Trucks: Our Top Picks

How to Make Air Conditioner Colder in Car (6 Best Ways)

If you have taken out time to read this guide (and have reached this part already!), it is evident that you might have encountered your car air conditioner blowing hot air instead of cold. And if this has happened, it might have made you uncomfortable in your journey during the hot summers as well.

So, what’s the solution? How to make your car AC blow colder air like before?

Now that you know the reason behind the car AC blowing hot air (mentioned in the above section) get to know how you can make the AC blow colder air in this section. Read along carefully

Start the AC After You Have Driven a Few Minutes

If you want to know how to make air conditioner colder in car and keep it damage free for a time period, switch it on after you have driven for a few minutes or more! It is readily advised that you never switch on the AC as soon as you start the car as it might drain the cooling system instantly.

When the car engine’s crankshaft starts rotating, the AC compressor works better, and thus, switching on the AC while the car is still parked can be a waste of both fuel and time without yielding better results also! It will also cool down faster than usual when you start the car AC while driving.

Avoid Pulling the Temperature to Maximum

If your car blows hot air when ac is on, you must first check out for the reasons mentioned above to find the exact cause. But if, in general, the car is not living up to the expectations of fulfilling the desired coldness inside the car while it is turned on, you might well make some changes to how you use it.

Please do not pull the temperature to maximum soon after you start it!

When you do so, the system actually takes up air from inside the car and cools it down to blow that cold air to you again. And the air inside the car is already hotter, of course! So, drive for some time at normal temperature, then turn to “max chilling” mode.

Stop Sending Mixed Signals to Your Car’s Cooling System

This is also one good reason why most car AC’s give up on their true self and produce warmer air than usual. When you keep on giving mixed signals to the car AC system, it eventually cannot keep up with the pace and thus starts functioning abruptly.

Thus, to make AC colder in car, you must stop giving it mixed signals like making it the coldest setting once and then turning it back to lower temperature and doing this more frequently!

What you must do is to turn on the coldest setting once and then arrange the fan setting if you feel hotter or colder during the drive!

Install AC Curtains and Park the Car on Shade Areas as Much as Possible

It would be best if you did not break your head thinking Why is my car air conditioner blowing hot air and how to fix it as you can achieve it easily by following simple methods like parking your car in shaded areas or even installing AC curtains.

These Are simple tricks that ensure your car AC blows colder air than the usual warmer air it blows.

When the car is parked in a shaded area or when you have installed AC curtains, it tends to keep the air inside the car cooler, which eventually leads to the AC picking up the cooler air and turning it into more cooler air during the journey!

Replace or Repair the Car AC Cabin Filter

When the car AC filter becomes worn out or dirty, it might lead to the breakdown of the entire cooling system of the car. As the name suggests, the car AC cabin filter is supposed to filter out all kinds of foreign substances, such as dirt, pollen, debris, etc., from the system to make air circulation easier and colder.

But if you recognize car AC not blowing cold air, you must understand that it is the cabin filter that needs to be replaced.

And if you do not change it on time, the extra pressure that it would create to push the air through the system can damage the AC even more. So, if you notice there is a problem with the car AC cabin filter, replace or repair it as soon as possible.

Turn Off the Recirculation Mode

If you’re still scratching your head thinking how to fix car air conditioner blowing hot air instead of cold air, then considering turning off the recirculation mode might prove to be of real help! If you turn off the recirculation mode of the car AC, the passengers at the back cabin will be benefited nonetheless.

The main work of the recirculation mode is to introduce cool air into the front portion of the car and then pull it back again, which leaves a spell of warm air in the back cabin of the car.

Thus, the ones sitting at the back are more likely to feel the warmth than the coolness of the AC. So, it’s better if you do not re-circulate the car AC to keep the warm air away!

Do you know? Why Your Car Smells Like Burning Rubber After Driving Fast?

Why is My Car Air Conditioner Not Blowing Cold Air? [FAQs]:

Most car owners seldom realize the fact that their car AC needs a repair or replacement until it actually starts blowing hot air instead of cold! And when this happens, it bores a big hole in your pocket, whereas if you recognize the problem earlier, it might be easy for you to solve the issue soon.

So, there might be some questions that must be bothering you, like car air conditioner repair cost or which brands products are best, etc. And to answer such queries, the following most frequently asked questions section is formed. Read on:

How to Tell What Refrigerant is in Your Car?

There are various types of refrigerants used in car air conditioning that most car owners have no idea about! So, how can you tell which refrigerant is present in your car cooling system?

Well, in most cases, you can find the name in the car AC system’s nameplate that is present under the hood. If it is not scribbled there due to any reason, you can still know it by calling the car’s dealer.

The most common refrigerant used today is the R-134A or the R-1234YF, but it is possible you find the R-12 variant in the older vehicles as well.

What is the Latest Refrigerant Used in Car Air Conditioners?

Most car owners try to find out What is the newest refrigerant for automobiles so that they can use it for better cooling purposes. And almost all automobile companies are now replacing the R-134a refrigerant with the new R-1234yf refrigerant.

It is considered suitable for environmental safety as it gives out a GWP of less than 1, and that is almost 99.9% less than the R-134a refrigerant. It provides the same cooling effect as that of the R-134a variant but with less environmental pollution because of being a fluorinated gas.

Apart from being environment friendly, the latest refrigerant also has fuel efficiency capabilities that the older variant did not have!

How Much Does It Cost to Fix Air Conditioning in Car?

Sometimes if your car AC is blowing hot air instead of cold and you have tried every possible DIY method to bring it back to normalcy, but have failed unanimously, then you must know that you have to take it for a repair!

And so, you must also be curious to know what is the average cost of car air conditioning repair, right?

Well, it depends on what kind of repair you are heading for! If you need compressor repairing, then it can cost you anywhere between $170 to $4000, depending upon the minor or major compressor repair. You may need $500 for AC hose repair, $100-$140 for recharging car AC and $200-$750 for compressor clutch repair.

Why is My Car Air Conditioner Making Loud Buzzing Noise?

If there is an issue with your car AC, then it is more likely that you might have noticed the car air conditioner making loud buzzing noise often.

There are different kinds of noises that your car AC can make, but if it’s a buzzing noise, then you must know that the car’s compressor needs a fix!

In most cases, the buzzing noise comes out when there is too much refrigerant on the car AC, so you get an overcharged system. And when the excess liquid starts entering the compressors’ intake port, it starts vibrating that in turn causes the buzzing noise.

How to Fix Car Air Conditioner Blowing Hot Air – Author’s View

Now that you know the reasons behind car AC blowing hot air and the methods to fix the issue, you might be feeling good enough to try at least a few of the given methods for a quick fix. While some car owners try to fix the issue by themselves, some prefer taking the car to the car mechanic to get the issues fixed.

Amongst the given few methods to fix car air conditioners blowing hot air instead of cold air, I would recommend 2-3 favorites of my choice that shall help you make the car AC colder and prevent blowing hot air as well. These are my recommendations:

  • Replace or repair the car AC cabin filter.
  • Avoid pulling the temperature to max or sending mixed signals to your car’s cooling system.
  • Install AC curtains and park the car on shaded areas as much as possible.

According to my understanding, these are some of the most coveted ways to improve your car’s ac performance. But before you jump to any conclusion, it is recommended that you first check out what actually is causing the trouble.

And if you are able to detect the problem with your car AC that is responsible for the hot air coming up from it, fixing it particularly can be helpful in preventing further sweaty interactions inside the car.

Hopefully, this article has helped you understand the reasons behind car air conditioner blowing hot air instead of cold air and the best ways to fix car AC not blowing cold air sometimes.

You may also be interested in checking out:

About Jace Cuban

I am an automotive enthusiast who loves to be around cars and pickup trucks. Applying innovative car care products and installing different latest car accessories are my hobbies. Also, I love sharing my adventurous experience with car lovers.

1 thought on “Why is My Car Air Conditioner Blowing Hot Air and How to Fix It?”

  1. Great! Informative.

    This was due to a refrigerant leak because your car did not have cold air flowing.

    I repaired it. After 15 days the same problem has fallen.

    Could it be due to improper repairs? Or is there any other problem?


Leave a Comment