Noises from the AC system are something you shouldn't ignore. Some are harmless, but others signal a problem that can escalate fast and cost you dearly. Here's what each type of noise means.
Clicking from the Dashboard
A light click when turning on the AC usually comes from the blend door actuator — the flap that directs airflow. If the clicking is brief and happens once, there's nothing to worry about. But if it's rhythmic and continuous, the actuator is likely worn and needs replacing. The cost is moderate — typically between 40 and 100 EUR including labor.
Squealing When AC Turns On
This is one of the more serious noises. A high-pitched squeal or screech when you hit the AC button usually comes from the compressor belt. If the belt is worn, loose, or cracked, it slips and makes this sound. Don't wait — a worn belt can snap while driving. At HOT22, checking the belt takes minutes.
Buzzing or Humming
A low-frequency hum with the AC running can come from the compressor. If the sound only appears with AC on and disappears when it's off, the compressor is likely strained due to low refrigerant or internal wear. A pressure gauge diagnostic quickly shows whether the issue is related to refrigerant levels.
Metallic Grinding or Rattling
Having a similar issue? Contact us for quick diagnostics.
This is the alarm sound. Metallic scraping or rattling from the compressor area means internal damage — worn bearings, a broken piston ring, or a loose clutch. If you hear this, we recommend turning off the AC immediately and visiting us as soon as possible. Running a damaged compressor can spread metal particles throughout the entire system, making the repair many times more expensive.
Knocking from the Fan Area
A leaf, twig, or piece of debris caught in the cabin fan can cause rhythmic knocking. It's usually harmless but annoying. A cabin filter replacement and fan blowout solves it.
When Is It Truly Urgent?
Act immediately if you hear: metallic scraping or grinding from the compressor, a sudden loud bang when AC turns on, or if the AC stops working after the noise. These symptoms mean mechanical damage that worsens with every minute of operation.
At HOT22, we have a full set of diagnostic equipment for AC systems. The check takes 20-30 minutes, and early diagnostics can save you 100-400 EUR on repairs. Don't ignore the noises — call 089 338 3443.
