11 reasons a car AC is not blowing cold air (& how to fix it)

As the entire country is often hit by sweltering heat during the hot summers, driving your car every day could feel uncomfortable. Fortunately, almost all vehicles have air conditioning systems as a standard. This option gives you the ability to combat extreme heat.

The air conditioning system only works when everything is operating as intended. Because it is a mechanical system, the air conditioning can occasionally fail as its components are prone to wear over time. 

car refrigerant

Below we will show you how your vehicle’s air conditioner works. Additionally, you will find out 11 reasons a car AC is not blowing cold air. We will also provide you with practical solutions and show you how to fix them.

The car AC stopped working suddenly.

There are many reasons why your car AC can stop working suddenly. Below, we will present you with the most common 11 reasons.

Reason #1 – Your car’s AC needs to recharge

It is the most common cause. Your vehicle’s air conditioner is not getting cold enough, so it might need to be recharged. You can do it yourself, but you should seek the help of a professional mechanic at your nearby auto shop.

Reason #2 – There is a refrigerant leak in your AC system

It can be difficult to detect because the refrigerant fluid can evaporate when it comes in contact with the air. But a skilled mechanic will have access to professional tools that will determine this cause for you.

It is often done by introducing ultraviolet fluids, which will show any signs of low refrigerant pressure in the system. Additionally, some other symptoms of a refrigerant leak include audible clicks or hissing sounds from the AC system. 

Reason #3 – Fan motor failure

The fan motor is located at the front of your car’s engine and can also be responsible for a faulty air conditioning system. While some cars will have one fan, others come equipped with two. It is important to keep these fans in good working condition to operate the system properly.

Reason #4 – Some sensors are malfunctioning

There are several sensors in your air conditioning system. If some of them fail, the functionality of this system is affected. Your vehicle has a central computer that collects data from several sensors. If the data is incorrect, the operations will be incorrect.

Reason #5 – Faulty cooling fan

automotive cooling fans

The condenser will require ideal airflow at all times in order to keep track of the high side system pressures. The cooling efficiency can be affected by a faulty cooling fan. You can easily identify this by noticing the cooling fan operating differently when your vehicle is idling and accelerating.

Reason #6 – Clutch failure

The compressor directly depends on the clutch, which engages the rest of the unit’s internal components. This clutch is released back into the default position when all power is withdrawn. But when the AC clutch fails, the engagement of the compressor is impossible. 

Reason #7 – Damaged compressor

A compressor is responsible for pressurizing the refrigerant. If this compressor lacks oil, it can quickly fail. Once this happens, all cooling systems will stop working, and the internal temperature in your car will begin to rise. After you experience AC compressor failure, it is recommended to flush the entire system.

ac compressor

Reason #8 – Contamination of the air

The AC system must be free of air and moisture contamination for proper operation. It will ensure maximum efficiency, so it is essential to keep it clean. Even the smallest amount of moisture will cause problems within the system. 

Reason #9 – System restrictions

Several restrictions will serve as the cause behind poor cooling. For example, a restriction can force the refrigerant flow, often leading to a strong fluctuation in the system pressure. As a result, the cooling process also fluctuates. The internal temperature cannot be kept at a constant value.

Reason #10 – Low refrigerant

R134 car AC

Another common cause is represented by low refrigerant. This low level is caused by a previously unknown leak within the system. You should always pay attention to the structural integrity of your components. A leak should be located and repaired as soon as possible. Otherwise, this problem will persist.     

Reason #11 – Excess refrigerant

While this problem is the opposite of low refrigerant conditions, it should still be considered as a possible cause of a faulty AC system. Excessive pressures can limit its efficiency, often caused by the system overcharging. It happens when you introduce additional refrigerant. You should always pay attention to the quantity and make sure you don’t exceed it.     

Car AC compressor running but not cooling.

Your day can get ruined quite fast if the air conditioning system of your car malfunctions all of a sudden. If there is a heatwave in your area, you might find your daily commute to be a difficult challenge. Most of the time, leaks or compressor issues are responsible for a faulty system.

If the compressor is running but not cooling, the fan or the radiator might be in trouble. Additionally, the malfunction could indicate that you need to recharge your AC.     

Turn on the AC at its maximum power and set the fans to a high level. Make sure that the clutch is engaging the compressor. Suppose the clutch is constantly engaging and disengaging often. In that case, it is a clear sign of low refrigerant, and you should increase its levels.   

Car AC blowing hot air after recharge

Let’s say that you are driving your truck on the Arizona roads. The heat becomes unbearable, so you finally turn on the AC. You expect a refreshing ice-cold breeze. Instead, you’re met with a blast of heat, which makes the experience even worse.

Some specific AC problems will feature this problem. The most common cause is the lack of refrigerant. However, you should also pay attention to the condenser as problems related to it will lead to the AC blowing hot air. 

If these work properly, other possibilities include broken cooling fans or a faulty compressor. The compressor is responsible for converting the low-temperature refrigerant into a high-pressure gas. 

The car AC is cool but not cold.

If your AC is cool but not cold enough for your own needs, it is rarely a result of a serious malfunction. In this case, the most common cause why the system doesn’t get cold enough is because it needs to be recharged. You can recharge the refrigerant by yourself, as it is an easy task.

However, you should make an appointment with your local mechanic. They will help you with this process and teach you more about the air conditioning system. Additionally, they can detect further serious problems such as a freon leak. 

The freon is a refrigerant that cools the warm air before it is blown into your car’s interior. A freon leak is critical and needs to be repaired by a professional. 

Best AC coolant

If you are looking for a coolant, look no further. We researched the entire market and chose the best AC coolant for you. 

AC Pro Car Air Conditioner Synthetic R134A Refrigerant

This high-quality product replaces the lost refrigerant and oil in your own vehicle’s system. The extra long 24-inch recharge hose allows easier access. You can effortlessly reach service ports situated in tight locations. 

It features a reusable trigger dispenser with a built-in low-pressure gauge and a temperature dial indicator to keep you updated in real-time. A customer had problems with the air conditioning system in his 2015 Volkswagen GTI. After he noticed that the system stopped blowing cold air after a while, he ordered this product.

The videos and instructions are easy to follow. After proper utilization, this customer was satisfied hence the positive review. If you struggle with the same problem, this product will easily solve it. 

InterDynamics
2,313 Reviews
InterDynamics
It's a great product.

Best tools for AC diagnostics

If you are looking for the most useful tools for diagnostics, these two models are the best ones we could find on the market. 

FOXWELL NT301 OBD2 Scanner Live Data Professional

FOXWELL NT301

This scanner enables you to locate bad sensors and access emissions readiness status. You can also read the live data and even retrieve the VIN of your vehicle. Foxwell developed this tool to read error codes for most cars accurately.

You can focus on any irregular data and trends with the aid of the vehicle’s sensor data. It is constantly displayed on the screen. This product features a 2.8-inch colored screen and a unique patented design, which makes holding it easy on your hand.

The read and erase hotkeys will allow an easier operation. At the same time, built-in speakers will indicate the readiness status. They will quickly alert you of any change. 

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FOXWELL NT301
22,272 Reviews
FOXWELL NT301
It's a great diagnostics tool.

MOTOPOWER MP69033 Car OBD2 Scanner Code Reader

The OBD2 has many practical multi-functions, such as a code read with a built-in library. It helps you quickly determine the cause of the problem. You can find the engine coolant temperature, engine speed, and more vehicle information.

An LCD display with a sharp resolution of 128 x 64 pixels features a white backlight and contrast adjustment. It allows this tool to be operated even during the nighttime or in environments with low visibility. This tool gets the power directly from your vehicle through the data link connector, so you won’t have to worry about batteries.

This powerful tool developed by Motopower is equipped with a 2.5 feet long cable made of a very thick and flexible insulator. On the scanner, you can find 6 buttons that will let you operate its various functions. 

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MOTOPOWER MP69033
15,990 Reviews
MOTOPOWER MP69033
Here's a budget option.

Why isn’t my car AC cold?

Troubleshooting the system is not difficult. However, the most common cause of this system malfunctioning is related to its recharging needs. You can recharge it yourself by using a refrigerant. After that, you can check if the AC is working. 

The vents should blow cold air soon after, but the problem is more extensive if the air is still not cold. Have a professional mechanic look at your vehicle. They will easily identify the cause and also come up with a solution for you. 

Fixing your car’s system is easy, and all you have to do is follow certain steps. Do not skip any of them, as they are all essential.

How to fix car AC not blowing cold air

  1. Start the vehicle and turn on the air conditioner.

    Turn on the engine by using the key and set the air conditioner on high power. Notice how the air feels when it comes out of the vents. If the air is warm or cool but not as cold as it should be, the system has a problem.

  2. Check the compressor and make sure it is running.

    Before determining the necessary repair actions, you must ensure that the air compressor is working properly. Locate this component in the engine bay and check if it works properly. 

  3. Check the wirings.

    Compressors will have a wire that leads to the electric clutch. You should find the connector in the middle of the wire and unplug it. Connect it to the positive terminal of your battery, and you should hear a loud clacking sound. It means that the electric clutch is functioning properly. If not, you will have to replace it.

  4. Look for leaks in the air conditioning system.

    Special leak detection tools will help you identify any cracks in the system. These kits often include a special dye that will run through the lines and make them visible to the naked eye. 

AC recharged, but it’s not cold enough.

If you recharged the AC, but it is still not blowing cold air consistently, you might have to check the refrigerant level. It is a fluid that passes around the entire system but it can evaporate at low temperatures. Eventually, it is condensed into liquid form when exposed to high pressure. 

FAQ

Does antifreeze help AC?

There is a type of refrigerant called Freon that helps the system cool your vehicle’s interior. Having such a coolant will help keep the temperatures low and ensure an optimal operation of your AC.

Does Autozone check air conditioning?

Autozone will test your AC unit using a special tool called a digital multimeter. This tool determines if the unit is receiving enough power and if the compressor works properly.

How much does fixing an AC in a car cost?

Depending on the severity of the issue, fixing an AC will cost you between $100 to $900. As more parts need replacement, this cost can further increase. 

How do I know if my car’s AC fuse is blown?

You can test the lines that bring the electrical power to the system. The reading should be around 220 to 240 volts. If you get the same result, there is no problem with the power supply. But if the reading is zero, it is a clear indication that the AC fuse is blown. 

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