What Causes the Ticking Sound in Car Air Conditioning Every Few Seconds?
2 Answers
Abnormal noises in car air conditioning are generally caused by internal or external issues within the air conditioning system. Internal noises often occur due to air or moisture in the refrigerant, which creates sounds during evaporation and expansion, typically perceived as coming from inside the dashboard. External noises are usually related to the air conditioning compressor, with the sound noticeable near the compressor. Below are other possible causes of abnormal noises in car air conditioning: 1. The noise is often caused by air or moisture mixed in the refrigerant. 2. If the noise persists after refrigerant recharge and is located near the compressor, there is a high probability of internal mechanical damage to the compressor. If the noise recurs after some time and originates from inside the dashboard, the desiccant bottle may have reduced efficiency. 3. The noise heard after starting the air conditioning is primarily the operational sound of the compressor and is not considered a malfunction.
I've repaired many car air conditioning systems before, and the clicking sound is usually due to relay issues. The relay in the AC system controls the compressor's start and stop, producing this sound every few seconds when it opens and closes. Aging relays or oxidized contacts causing poor connections are common causes. Another possibility is the expansion valve working, which can produce rhythmic clicking sounds when regulating refrigerant flow. Although the sound is small, if left unaddressed, the AC might suddenly stop cooling, especially on hot days while driving, which can be quite troublesome. I recommend checking the relay box as soon as possible and trying to replace the relay. Regular maintenance, such as keeping AC components clean, can reduce such failures and avoid bigger repair costs.
