What is the reason for the hissing sound when the car air conditioner is turned on for a while?
3 Answers
The reason for the hissing sound when the car air conditioner is turned on for a while is insufficient refrigerant. Below is an introduction to air conditioner maintenance: 1. Choose the appropriate air conditioner temperature: When the temperature is set too low, it can affect health, so the air conditioner temperature should be adjusted appropriately. The most comfortable temperature for the human body is between 20°C and 25°C. Above 28°C, people will feel stuffy, while below 14°C, they will feel cold. Therefore, the car air conditioner should maintain the temperature between 18°C and 25°C. Setting it too low can easily make people sick. 2. Immediately activate the recirculation mode when entering the car in summer: When first entering the car, you should open the windows for ventilation and turn on the external circulation to expel the hot air. After the temperature inside the car drops, switch to the recirculation mode.
When I encounter a hissing sound after turning on the car air conditioning, it's usually due to the refrigerant flowing through the pipes during the initial system startup, which is a normal phenomenon. The release or pressure adjustment of high-pressure gas during air conditioning operation can produce a hissing sound, similar to air release. Many vehicles make this noise when starting up, especially during the first few minutes of cooling. If the sound is not loud and quickly disappears, and the air conditioning cools normally, there's no need to worry. However, be alert for any accompanying strange odors or lack of cooling, as these could signal a malfunction. It's advisable to maintain regular system maintenance and avoid turning on the air conditioning immediately after high-temperature operation. If still concerned, having a simple check at a reliable auto shop can provide peace of mind.
I think this sound is most likely a sign of refrigerant leakage. When the air conditioning starts, if there is a tiny leak in the high-pressure pipeline, the refrigerant will leak out and make a sound similar to gas release. This is commonly seen in cars with aging pipelines or loose joints. If not repaired in time, it can lead to poor cooling performance or even complete failure. During my usual repairs, I've found many older cars have this issue. The simplest method is to listen carefully for the sound location after turning on the AC or spray some soapy water to find bubbles and confirm the leak point. It's best not to delay; take it to the shop immediately to replace the parts or fix the leak.
