Reasons Why Your Car AC is Not Blowing Cold Air and What to Do About It

Alana Grace

Close-Up Shot of a Car Button
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Are you struggling with a car AC that’s not blowing cold air during the hot summer months? You’re not alone. This article will guide you through the reasons behind this common issue and how to fix it.

Diagnosing car AC problems can be complex. However, the basic concept is much easier to understand when the components are broken down. This article will guide you through the reasons behind this common issue and how to fix it.

Understanding Your Vehicle’s AC System

Your vehicle’s AC system compresses and heats the refrigerant, then allows it to decompress and condense into a liquid that causes it to rapidly lose heat. This process absorbs heat from the car’s cabin and is continuously repeated to achieve your desired temperature.

The compressor runs off an engine belt that squeezes or compresses the gaseous refrigerant. Once it has been pressurized, the condenser cools it down through a series of finned tubes where it returns to a liquid state. This liquid will then pass through a dryer or receiver that removes excess water to eliminate the risk of ice crystal formations inside the AC system.

Next, the liquid refrigerant enters the evaporator via a thermal expansion valve where it is then exposed to heat from the vehicle’s cabin. At this point, the fluid boils, reducing it to a gas form once again. During this process, the heat from the surrounding air is absorbed causing the evaporator coil to chill. Finally, it is redistributed throughout the cabin by the blowing fan through the vents as cool, crisp air-conditioned air.

Your car’s AC system is designed to provide you with a comfortable ride, especially during the hot summer months. However, sometimes problems occur. The most common causes of a malfunctioning air conditioning system are leaks or compression issues. If you are feeling cool — but not cold — air, the issue could be a clogged filter, a problem with the cooling fan, signs of radiator trouble, or it could simply mean it’s time to recharge your AC.

Common Reasons Why Your Car’s AC Doesn’t Run Cold

Car interior / Air conditioner
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Check the Cooling Fans and Condenser

If the air conditioning is set to the max cool setting but is only blowing slightly cool air, you should:

  1. Check to see that the cooling fans on the condenser or radiator are running when the air conditioning is on.
  2. Look for any restrictions like leaves, bugs, or dirt that could be preventing air from passing over the condenser.
  3. Check the cabin air filter to make sure it’s not clogged.

Inspect the AC Compressor

When trying to get the source of your AC issue, it’s best to begin at the compressor. To do this, follow these steps:

  1. With the engine running, turn the AC on max cool. Set your fans to high, and make sure that the clutch is engaging on the compressor.
  2. If the clutch is not engaging and the system has refrigerant, use a voltmeter to check for voltage getting to the compressor. The clutch may be bad if there is voltage. If there is no voltage, a cycling switch may be bad, a fuse could be blown, or the system may not have enough refrigerant pressure to trip the low pressure cutoff switch that cycles the compressor.

Detect Possible Leaks

One of the most common reasons air conditioning systems experience problems is due to a leak. If air pressure is low, it could signal a leak. To check for a leak, follow these steps:

  1. The easiest way to detect a leak is by using a UV AC leak detection kit.
  2. If you don’t have a kit, check around all fittings to make sure they are all secure.
  3. Check hose manifolds on the compressor.
  4. Look at the front seal and the o-rings sealing the pressure switches on the back of the compressors.
  5. Check where the hoses are crimped onto the fittings.
  6. Look at the Schrader Valves.
  7. Check for pin holes in the condenser.
  8. Look where the evaporator drains condensation with UV light. Sometimes oil or dye can be seen.


So, that’s all about what to do if your car’s AC doesn’t run cold. However, before you decide to fix it by yourself, make sure that you are ready to face any risks of this. In addition to that, do not forget to contact a professional if you are unsure about the correct diagnosis of your car’s failing air conditioner. All you need to do is to schedule an appointment with a certified mechanic.

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