Car Air Conditioning Not Cold? 5 Things to Check

 When the summer heat arrives and your car's air conditioning blows warm air, it is not only uncomfortable. It can be a sign of a small problem that is easy to fix, or of a bigger one that needs a professional. Check these five things first.

A weak A/C often has a simple cause you can check yourself.
Photo by Philipp Katzenberger on Unsplash

5 things to check

1. The settings. Make sure the A/C button is on, the temperature is set to cold, and the recirculation mode is on. Recirculation cools the cabin faster than pulling in hot outside air.
2. The airflow. If the air is weak, the cabin air filter may be dirty. A blocked filter reduces airflow and can cause a musty smell. Many cars let you replace it yourself in a few minutes.
3. The front of the car. The condenser sits behind the grille, in front of the radiator. If it is covered with dirt, leaves or insects, it cannot release heat well. Clean it gently, without bending the fins.
4. The compressor. With the engine running and the A/C on, listen for a click when the compressor starts. If you never hear it, there may be an electrical problem or a low refrigerant level.
5. Leaks and refrigerant. A weak A/C is often caused by a refrigerant leak. Topping it up does not fix the leak, and the gas will escape again.

When to see a professional

If the simple checks do not help, go to a garage. Refrigerant handling needs special equipment, and too much or too little gas can damage the compressor. Strange noises, a hot smell or a cooling fan that does not turn are also reasons to stop and get it checked.

Prevent problems

• Run the A/C for a few minutes regularly, even in winter, to keep the seals lubricated.
• Replace the cabin filter as your manual says.
• Turn the A/C off a minute before you park and let the fan run, to reduce moisture and bad smells.

Safety note

In hybrid and electric cars, the compressor is often powered by the high-voltage system. Leave any work on it to a qualified technician.

Golden tip: Park in the shade, or use a sunshade. It reduces the heat the A/C has to remove.

What is your best trick for a hot car in summer? Tell us in the comments.

This article is for general information only. Cars differ, so always follow your owner's manual and ask a qualified mechanic if you are unsure.