In most cases, it is normal for the noise in a car to increase after turning on the air conditioning. Air conditioning is commonly used in summer, and there are also many malfunctions related to the air conditioning system. Some of these phenomena are not related to malfunctions, and some novice drivers may not understand and may go to the 4S store for inspection. For example, if the noise becomes louder when the air conditioner is turned on, and water drips under the engine, going to check is like running for nothing, wasting fuel costs and one's own time. Now let's talk about why the noise increases after turning on the air conditioning? What kind of noise is abnormal?

The biggest noise we hear after turning on the air conditioning is from the high-speed operation of the electronic fan. A car with good sound insulation does not sound so obvious inside the car. When standing outside, especially near the front of the car, one can clearly feel that the noise is very loud. This is very normal. The electronic fan makes a loud noise when running at high speed, but the noise level varies depending on the vehicle model, and some models have particularly loud noise. Another noise comes from the engine. When the air conditioning is turned on, the engine's idle speed will increase by about 100 revolutions. Because the compressor starts working and the engine load increases, it is necessary to increase the speed to supplement power, otherwise there will be poor operation and unstable idle. So when listening outside the car, besides the sound of the electronic fan, the engine speed is high and the noise is also higher. But it's not so obvious, the noise will be covered by the electronic fan, and the noise from the electronic fan is really too loud.

Why not turn on the air conditioning and the electronic fan doesn't run at high speed? The electronic fan operates to dissipate heat from the water tank and condenser. It has two gears, low speed and high speed. If the air conditioning is not turned on, it only rotates to dissipate heat from the water tank. Do not turn on when the water temperature is low, and only turn on when the water temperature is high. In most cases, starting the low-speed gear can provide good heat dissipation, and there is no need to turn on the high-speed gear. The noise in the low-speed gear is very low and does not sound obvious. If the temperature is very high and the vehicle load is relatively high, the high-speed gear will also be activated, but it will stop shortly, and the driver often does not pay much attention.

After turning on the air conditioning, the condenser needs to have good heat dissipation at all times, otherwise the cooling effect of the air conditioning will deteriorate. So regardless of whether the water temperature is high or low, the electronic fan must operate at high speed to ensure good heat dissipation of the condenser. In addition, after turning on the air conditioning, the engine load increases, which also generates more heat and raises the water temperature. Both the water tank and condenser need to dissipate heat, so the electronic fan can only operate at high speed so that both have good heat dissipation conditions.

Of course, if there is a malfunction in the compressor or pulley, there may also be an increase in noise after turning on the air conditioning. However, this is considered abnormal noise and is not normal. How can we distinguish it? If there is abnormal noise, two obvious noises can be heard: the whining sound from the electronic fan, mixed with other sounds, commonly including rustling and squeaking. These two sounds are sharper than the others and can be easily heard. That is to say, it is normal for the noise to be single, only a whimper. The noise is not uniform, with two sounds mixed together, especially one that is quite sharp, which may be abnormal. Please go to the 4S store for inspection and confirmation in a timely manner.

From: WONDEE Autoparts

2024-4-24