What Causes the Engine Noise When Turning on the Air Conditioning?
2 Answers
It is normal for the engine to make noise when the air conditioning is turned on. After activating the cooling function of the air conditioning, the engine needs to drive the compressor to operate, which increases the idle speed of the engine, resulting in the noise. Below is more information about car air conditioning: 1. The car air conditioning is an important comfort feature in a vehicle, and its cooling principle is quite simple. When the AC button is pressed, the clutch of the air conditioning compressor engages, and the engine drives the compressor to operate. 2. The compressor continuously compresses the refrigerant and delivers it to the evaporator. The refrigerant expands and absorbs heat inside the evaporator, thereby cooling it.
Last time I took my car on a long trip, the weather was scorching hot so I turned on the AC. Suddenly, the engine started roaring loudly. At first, I thought the fan was broken, but when I asked at the repair shop, the mechanic explained that the engine bears a heavier load when the AC compressor kicks in. When the compressor engages, it connects to the engine system, causing a slight drop in engine RPM and a bit louder noise—this is quite common. However, if the noise is unusually harsh or continuous, you should be cautious. It might be due to an aging, loose, or slipping belt, or the compressor bearings might be worn out, causing friction sounds. I once tried parking in a safe spot, turning the AC off and on to listen for differences. If the noise becomes more noticeable, it’s likely time to replace the belt or inspect the compressor. Delaying repairs could lead to increased fuel consumption or reduced AC cooling efficiency, so it’s best not to procrastinate. Regular checks on belt tension and maintenance of AC components are good preventive measures.
