Car AC not Blowing Cold Air? - Common Causes

Possible Refrigerant Leak

Car AC Not Working Due To Electrical Issues

Blocked or Broken Condenser

AC Compressor Might Be Faulty

There’s Mold and Mildew Build-up

How To Maintain Your Car’s AC System

Keep Your Car’s AC Working Properly

Your vehicle’s air conditioning system may not be working correctly for several reasons, ranging from faulty compressors to refrigerant leaks. According to an analysis by Consumer Reports, some car models like the 2015 GMC Acadia and the 2013 BMW X5 are simply prone to AC problems.

If you start noticing your AC blowing out warmer air than usual, there might be a problem worth checking. This article will share some of the reasons your car AC is not blowing cold air and helpful details on assessing each problem quickly.

Possible Refrigerant Leak

Your car’s refrigerant is the one that keeps your cabin cool, and a leak in your refrigerant might be a reason your car’s AC is not working correctly.

When the refrigerant is not being pressurized in the compressor, it becomes gas that circulates within the sealed environment of your AC system. If your AC is blowing warmer air than usual, a significant leak may be present.

Aside from noticing the warm air, there are two other ways to check for a refrigerant leak:

  • Listen to the AC Clutch: Whenever you turn on your car’s AC, listen carefully; you should hear a clicking sound. The sound signifies the AC clutch being engaged. If a leak is present or the Freon levels are low, the clutch will not engage.
  • Visible leaks: After parking your car from a drive, check for visible leaks on the floor of the driver’s seat and under the vehicle. If you notice a greasy substance leaking out, especially near the compressor, it could be a refrigerant leak.

Normal wear and tear is usually the cause of most refrigerant leaks, especially in aging vehicles. However, accidents on the road like under-car damage caused by rocks and potholes can also cause leaks.

Fortunately, auto care experts should be able to repair the leaks in under 5 hours, depending on the extent of the damage. The average cost ranges from $150-$800.

Car AC Not Working Due to Electrical Issues

car dashboard

A car’s air conditioning system is electronically operated. When there are blown fuses or damaged wires, your car’s AC may stop working altogether.

AC electrical issues are common for those living in climates with outside temperatures going above 45 degrees. Too much exposure to the heat can cause the electrical wires to short circuit and cause other damage to the internal wiring.

An AC system with electrical problems will usually not run at all. In some cases, you may notice the AC going off and then turning itself on again while driving.

If you are an experienced electrician, it’s possible to conduct your repairs by tracing where the wire has been damaged, sealing it with electricity-resistant tape, and reconnecting any broken wires.

However, if you are unfamiliar with fixing electrical wiring, it’s best to rely on a professional to diagnose and repair the issue. What you shouldn’t do is ignore the problem. Electrical problems can eventually lead to acid build-up, which can corrode internal components enough that you may have to replace the entire AC system completely.

A simple wiring repair could take as fast as 15 minutes, depending on the issue. Severe electrical damage from acid build-up could take hours, especially if it involves replacing the AC system. The average cost of electrical repair can take around $200.

Blocked or Broken Condenser

car air conditioner

An issue with the condenser can be another reason your car’s AC is blowing hot air. The condenser is what cools the refrigerant, which in turn converts hot air to cool air.

The condenser is found in the car’s front area to catch the air the vehicle is traveling through and use it for the air conditioning process. Though strategic for the AC system, this position exposes the condenser to debris, dirt, and even garbage, which may result in blockage.

Blockage makes it difficult for air to travel through the condenser. Not only will this cause your AC to blow hot air, but it can also overheat the vehicle and severely damage the condenser.

Other signs indicating issues with the condenser:

  • There is a burning smell: When driving, your car will be unable to exhaust the heat produced because it’s working on the AC system. Issues with the condenser can cause a significant increase in temperature, which can cause some components to start burning. Your AC will then begin to blow warmer air along with a foul, burning smell.
  • Car overheats while idling: Condensers are cooled by the constant airflow. Any blockage to the airflow can cause the condenser to overheat. The high temperatures will prevent the refrigerant from circulating correctly and eventually fail to exhaust heat. These factors may eventually lead to your car overheating.


Fortunately, problems with the condenser can be prevented through regular car maintenance. Inspecting your car’s front grille and having it cleaned every two weeks or after a long drive can help avoid any dirt build-up.

A damaged condenser needs to be replaced. The average cost of a condenser replacement ranges from $585 to $773. Condenser replacement services usually take 3 to 5 hours.

It’s common for the car’s compressor to misbehave and blow out hot air after months of not being used.

AC Compressor Might Be Faulty

car dashboard knobs

Your car’s compressor pressurizes and circulates the refrigerant, which helps remove the heat from the cabin. If the compressor malfunctions, it causes the car’s AC to blow hot air.

It’s common for the car’s compressor to misbehave and blow out hot air after months of not being used. Turning on the AC after winter, for example, may take 15 to 20 minutes before the compressor starts working as intended. Any longer than that may be a sign that the compressor is faulty.

Apart from blowing hot air, you can determine if the compressor is faulty by noticing these signs:

  • Skipping or squealing noise: Compressors contain several moving parts. If one of these parts is faulty, it usually produces loud squealing noises from under the hood. Try turning on your car’s AC and set the fan speed to max. If a loud noise is produced and only goes away after turning the AC off, the compressor might be faulty.
  • Inability to turn AC on or off: If the compressor’s clutch is broken, you may not be able to turn your AC off or on. Usually, it’s the latter. Without the clutch, the compressor doesn’t receive power from the engine, leaving your car without air conditioning.

Finding the faulty component of a compressor is difficult, even for experienced car technicians. In most cases, car compressors will have to be replaced. The average cost of a replacement, including the labor, will net you $900. The replacement process can last 4 to 6 hours.

There’s Mold and Mildew Build-up

Mold and mildew tend to accumulate in the AC system, especially without regular maintenance. Enough mold buildup can interfere with the cooling procedure and cause the AC to produce warmer air.

Mold and mildew buildup also produces a distinct and unpleasant odor that can be hazardous to humans. Mold exposure can trigger asthma, cause wheezing, and cause allergic reactions.

Experts recommend having your AC system checked and cleaned every two years or at the first sign of mold. Expect to pay $100 to $300 for a full-service inspection and maintenance. The process can last as quickly as 20 minutes or an hour.

A lot of car AC issues are usually due to low refrigerant levels.

How to Maintain Your Car’s AC System

man holding the steering wheel

While an auto care professional can resolve most issues, proper maintenance is still the best way to prolong your AC system’s life. Here are some practical maintenance tips that will help improve your car AC‘s performance.

Avoid Precooling

A car’s AC system works better when you’re driving. The compressor runs faster when the engine is turning, allowing the AC system to cool more effectively. Avoid wasting time and fuel by letting your car run before you drive.

You can turn on the air conditioner and open the windows for at least 20 seconds as you start driving. The air inside the car will always be hotter regardless of the season or climate. Opening the windows will help level out the temperature and prevent your AC system from working too hard at the start.

Turn On the AC Regularly

Always turn on your car’s AC for at least 10 minutes every week. Set the temperature to its coolest setting and the fan at its quickest option. Doing this every week will maintain the gas pressure and help keep the compressor at peak condition, preventing any mechanical issues from developing.

If your car’s AC system has a defrost setting, run it for 10 minutes every week as well. Running defrost regularly helps remove any moisture present and prevents the development of mold or mildew.

Check the Air Filters

Dirty air filters prevent air from flowing correctly and force the AC system to work harder. Regularly check your car’s air filter to make sure it’s clean. If you notice too much dirt on the air filters, it’s best to have them replaced. Air filters on modern cars are usually accessible behind the glove compartment. Check your car’s manual to locate the air filters.

Have Your AC System Recharged

A lot of car AC issues are usually due to the low level of refrigerants. Like other essential car fluids, refrigerants get diminished over time, so make sure to recharge regularly. You can check your car’s service manual for the recommended recharge time, but it’s usually every two to three years.

Keep Your Car’s AC Working Properly

The hot air blowing from your car’s AC is usually a sign of a bigger problem. It’s wise to consult an auto care professional immediately at the first sign of AC issues to address the problem and prevent further damage.

Fortunately, car experts like Auto Works of Brandon can help you determine any possible AC system issues. Our team of auto care professionals will take care of your car’s AC problem quickly and efficiently.

If you’re looking for experts to look at your vehicle’s AC system, contact us today for an appointment, and we’ll diagnose any AC problems you have.


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