What Causes the Noise in the Car's Air Conditioning Expansion Valve?

[SanRonan]

The reason for the noise in the car's air conditioning expansion valve is that the expansion valve is blocked. Below is an introduction to the causes of air conditioning not cooling: 1. Internal damage: Severe internal wear of the compressor leads to its inability to function properly. 2. Oil stains: The presence of oil stains at connections or seams indicates refrigerant leakage, requiring reinforcement or replacement of related parts. 3. Circuit system failure: Circuit system failures causing the car's air conditioning compressor to malfunction are also very common. You can check if the circuit is unobstructed, inspect the temperature sensor solenoid valve, and other potential fault causes. 4. Low-pressure gauge reading much lower than normal: The surface temperature of the compressor suction pipe is lower than normal, appearing damp and cold (commonly known as sweating).

[ODerek]

I found that when the car's air conditioning is turned on, there is abnormal noise from the expansion valve, which is usually caused by poor refrigerant flow, such as blockage inside or insufficient refrigerant. This can produce a buzzing or hissing sound. If the refrigerant is low, the pressure becomes unstable, and the valve core is prone to vibration, resulting in noise. If there is dirt blocking the valve body, the airflow impact can also cause abnormal sounds. If not addressed in time, the air conditioning will become less and less effective, and may even lead to compressor wear, making repairs more expensive. I usually recommend that car owners regularly inspect the air conditioning system, at least once a year, to check the refrigerant level and clean the pipes. After parking, don't turn off the air conditioning immediately; wait a few minutes to let the system stabilize, which can reduce the burden on the valve components. Remember, safety comes first. If the noise is severe, it's best to go to a professional shop to test the pressure to avoid major problems while driving.

[VanJohnny]

My car had a similar issue before, the AC expansion valve would make a noise that made me nervous, probably due to debris stuck inside or the valve aging and deforming. This component controls refrigerant flow, and when it malfunctions, the noise can resemble dripping water or friction sounds, which is not only annoying but also affects cooling performance. If left unrepaired, the AC might fail, making summer drives unbearably stuffy – definitely not worth it. I recall the mechanic simply cleaned it or replaced the valve, which wasn't expensive. If attempting DIY repair, be cautious about system safety and avoid touching high-pressure parts. For routine maintenance, consider adding high-quality refrigerant and checking pipelines for leaks. Inspect the AC filter weekly for dirt buildup – prevention is always better than dealing with a breakdown on the road.

[SanLorenzo]

Noise from the expansion valve is mostly due to insufficient refrigerant or internal valve sticking, producing an annoying squeaking sound. This affects AC efficiency, reducing cooling power and increasing fuel consumption. Get it checked at a repair shop ASAP—a mechanic can diagnose the issue with a pressure gauge. Maintaining the system and regular refrigerant replacement can prevent 90% of such failures.