Why does the car make a hissing sound like air leakage when the air conditioner is turned on?
2 Answers
Car makes a hissing sound like air leakage when the air conditioner is turned on is the refrigerant airflow noise caused by the throttling of the expansion valve in front of the evaporator in the car air conditioning system. As long as the operating condition is slightly changed, such as adjusting the fan speed, the sound will disappear. The car evaporator is a component in the air conditioning system. Its function is to allow low-temperature condensed gas to pass through the evaporator, exchange heat with the outside air, absorb heat through liquefaction, and achieve the cooling effect. Car air conditioning refers to the air conditioning device installed in the car, which can cool, heat, ventilate and purify the air in the compartment, providing a comfortable riding environment for passengers, reducing the driver's fatigue and improving driving safety.
I've experienced the hissing sound from the AC while driving multiple times. It's usually caused by refrigerant leaking from the pipes or connections, as the high-pressure gas escaping creates that hissing noise. Aging pipes, loose connections, or small holes in the condenser can all lead to this issue, especially in older vehicles. If left untreated, the AC cooling performance will gradually deteriorate, making summer drives miserable. My advice is not to ignore it - get it checked at a repair shop ASAP. They use specialized leak detection tools to pinpoint the problem. By the way, pay attention to AC pressure gauge readings during routine maintenance - early detection means cheaper repairs and avoids major expenses.
