Car AC not cooling: the most common causes

Air conditioning is especially important on hot summer days, but sometimes it doesn’t cool properly. You can find out why that can be and what you can do yourself in our home about it.

The air conditioning system is used when the open windows in the car are no longer cooling. However, if you find that the cooling effect is missing, you should go on troubleshooting. This article lists the most common causes.


First think about when you last had your air conditioning refrigerant refilled. The consumption or loss of refrigerant is relatively low, but something is always lost over time. Therefore, you should have the amount of refrigerant checked every two years. You can only have refrigerant refilled in a workshop.


The condenser ensures that the refrigerant releases the heat. Since it is installed in the front part of the engine compartment, it is often damaged by small stones. The stones can hit the condenser so quickly that you can seriously damage the thin slats. In this case, the condenser fails and the air conditioning no longer works. Have it checked in a specialist workshop.

Foliage remnants

Especially in the beginning of autumn, leaves collect in front of the cooler. The air conditioning will no longer work on the hot days in autumn. You can remove the foliage yourself and then quickly find out whether it was the cause. Dirt can also clog the cooler and thus prevent the cooling effect, you should also clean the cooler regularly in summer.


If all of the previous causes are not applicable to you, the compressor may be defective. It processes the refrigerant under high pressure. Your car’s compressor has many moving parts that can get stuck over time. This is particularly the case with older models and especially when the air conditioning system is used little. Have the compressor checked in the workshop.


A common reason that is neglected is a broken switch. You can easily find out whether the switch is defective. To do this, start your car and press the switch, you should now hear the compressor and the condenser. If there is no noise, this can indicate a defective compressor or condenser, but also a defective switch.

Tip: Always switch the air conditioning on again on cooler days, as this lubricates all moving parts. It also prevents the refrigerant from becoming moldy and smelly. If you have the air conditioning system serviced regularly, it will serve you well for a very long time.

Author: Nabeel K

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