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Car AC Not Blowing Cold Air: 12 Causes & Solutions

Your AC not blowing cold air on a sweltering day can feel unbearable. Hot air blowing through your vents could signal a minor or major issue. You could have a leak, clogged filter, cooling fan problem or some other issue. By knowing all of the reasons, you can better explain them to a mechanic or even solve them yourself.


Understand the Air Conditioning System

AC systems all run the same way, no matter the make and model of your car. Some systems may be more complex than others, but the basics are the same. The three main parts of the AC system are the compressor, condenser, and the evaporator.

\Refrigerant is the high-pressure gas that is compressed into a fluid. Your car’s condenser removes the heat from the fluid using a series of tubes. A dryer or receiver removes excess water to avoid ice forming inside the car. Refrigerants are exposed to the heat in the car’s interior via the thermal expansion valve, which operates as an evaporator. Your AC system absorbs the heat from inside of the car in a continuous manner. Some vehicles may only have low, medium, and high AC settings whereas others may allow you to set a specific desired temperature.


12 Causes & Solutions to AC Not Blowing Cold Air

1. Low or Empty Refrigerant

One of the most common reasons for warm air blowing through the car is a refrigerant issue. The decline may be slow. At first, it may just be a degree or two warmer than you thought it would be. However, over time, the lowering refrigerant will only worsen as the AC system runs.

With frequent use, the fluid will need to be replaced, especially after increased use, If you are running low, then the AC will not operate efficiently. Pay attention if it takes longer to cool the car’s interior. Once you refill the refrigerant, you will have cool air flowing through the car.

Read our Article: How do I know my car AC needs recharged?

2. There Could be a Leak In Your Car AC System

Leaks are another common issue with AC systems. This is a harder issue to spot because you may not see any leaking because the fluid evaporates when it touches air. There are a few things car owners can look out for. First, listen for a click when the AC system turns on.

Another sign of a leak is if your system frequently cycles off and on. Other signs include hissing sounds when the engine is turned off and oil near the AC fittings, parts and hoses. Make sure to inspect seals and hoses for gaps and holes. It is important that all of the parts are properly attached to avoid leaks.

Mechanics can use specific tools that use ultraviolet fluids to see if there are signs of a leak. If too much fluid has been lost, mechanics may need to flush out the whole air conditioning system to replace the fluid. You should be careful around refrigerant since this is a toxic chemical. Trained professionals understand how to handle the fluid without harm.

3. Inspect the Compressor

Remember that the compressor is basically a pump that rotates so that the refrigerant moves throughout the AC system. Turn the car on and pay attention to the compressor. You may have an issue if the clutch is not properly engaging. It could be a sign that the compressor has an issue or that there is low refrigerant. Mechanics use a voltmeter to inspect if there is enough power or voltage flowing through the compressor. If power is not getting through, then there could be a blown fuse affecting the AC.

4. Issues with the Fan Motor

Another common issue for AC failure involves the fans. The fan may need to be cleaned, or it may need to be replaced. Some cars have one fan whereas others have two. Listen for any sounds with the fans. A fan in need of replacement will make straining noises.

fix ac issues by changing air filters

5. Filters and Clogs

If you set the system to max cool and it has warm or moderately cool air flowing, check to see if the filters need to be replaced. Over time, dirt, dust, and debris get caught in these. Mechanics can easily replace the filters, which not only enhances the AC system but also improves the air quality. Next, look to see if there is anything clogging the vents. Something as simple as some leaves or hair could affect the air conditioning system

6. Air Conditioning Accumulator

The accumulator absorbs a lot of fluid moisture. Too much moisture can be really harmful to the compressor and overall system. In some ways, it is like having too much water or sugar in gas.

7. Expansion Valve

The expansion valve regulates the air flow throughout the vehicle. Some cars will have an expansion valve whereas others have a similar orifice tube. If the valve is malfunctioning, then the AC regulation may be too high or low.

8. Loose Connections

Loose connections not only cause leaks but affect the regular flow of cool air. Every piece of your car’s AC is integral to temperature regulation. A loose gasket disrupts the delicate balance of the system. Simple fixes include replacing damaged hoses, fixing gaps and tightening connections.

9. Electrical Problems

It’s also possible that there is a very simple reason your car air conditioning is not cold, and that is electrical. Some of your A/C system’s parts, including your compressor, are electrical. And something as simple as a blown fuse can cause it to stop working.

10. Blend Door Stuck

Cars have heating and cooling systems. A blend air door helps your car move from the heating system to the air conditioning system. This door covers the ventilation system to keep warm air out and keep cold air in. The blend door sometimes gets stuck, which is why you have warm air flowing through the vehicle. The door is behind the dashboard and not always easy to see or reach. It may not need to be replaced. Mechanics know how to reach and fix the blend door.

11. AC Electrical Problems

Many parts of the car’s air conditioning system are electrical. This is another common issue for warm air flowing through your vehicle. Blown fuses can also affect other parts of the car too, so it is important it is replaced.

12. No Air Problems

Sometimes the issue is not warm air but no air flowing through the car’s interior. This could signal that there is a motor issue or there is blocked air intake. Your car’s blow resistor regulates how much air is blown through the vents. Additionally, you should know there are two main areas where air comes into a vehicle. The first access point is near the lower half of the windshield and the other access point is the air recirculating throughout the car’s cabin. Issues with the car’s belts could also cause the issue.

Know the Signs of a Faulty Car AC


Car Air Smells Strange

Pay attention if the air in your car smells dank or strange. There could be a major issue if you smell something like mildew coming through the vents. Foul odors mean that there could be bacteria growing in the system. Older AC systems experience this more than newer ones. Extra moisture in the vehicle could cause mold, fungi and other growths. Behind the dashboard is a common place for micro-organisms to grow. The odor you smell is a sign that you need professional support. In addition to replacing the filters, it is important for technicians to clean the system using an anti-bacterial solution. If you do not handle mold quickly, it will spread.

Weird Car AC Noises

Air conditioning systems should be silent. You should only hear the air coming into the vehicle. If you hear rattling, clanking or loud banging, then there is an issue. There could be a blockage, or there could be a malfunctioning part.

Water on the Floorboards

Water is a big sign that there is a serious problem. After all, the refrigerant evaporates when it means air. Bacteria growths cause slimy films, which can then cause clogs. Drain lines may be damaged and casing this issue too.

Knowing how your car’s air conditioning system works means you can better diagnose issues. Pay attention to the warning signs. Parts could be damaged due to wear and tear, your refrigerant may need to be replaced, or there could be leaks or growths affecting your car.

The sooner you catch an issue, the easier it is to repair. No one wants to deal with a hot humid day without their AC system working. Thankfully, most AC issues are easy to repair when handled by professional car AC repair experts like Mac’s Radiator. We are located in 6 convenient locations, for when you need us close to home, or when you’re on the road.

Macs Radiator services Air Conditioning Systems! Go to our AC Service and Repair page to learn more.



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