What Causes Abnormal Noise in the Engine When Turning on the Car Air Conditioner?

[StJameson]

Engine abnormal noise can be caused by engine misfiring, improper use of engine oil, timing belt noise, insufficient car warm-up time, and other factors. Below is relevant information about the engine: Relatively small friction torque: The engine valve drive mechanism adopts a hydraulic support roller rocker arm structure. Compared with the hydraulic tappet valve drive mechanism commonly used in modern gasoline engines, this innovative valve drive mechanism has the advantage of relatively smaller friction torque. Reduced camshaft weight: The use of a heat-shrink camshaft, compared to the original camshaft, not only reduces the weight of the camshaft but also allows the engine to achieve higher camshaft profile accuracy and more precise valve timing.

[DiJack]

As a veteran driver with over a decade of experience, I've encountered numerous cases of engine noise after turning on the AC. The most common cause is a loose belt - when the AC is activated, it produces a squeaking sound from the belt slipping against the pulley, requiring immediate adjustment or replacement at a repair shop. Worn compressor clutch is another major issue, creating a rattling noise that could potentially damage the entire compressor system if left unattended. For the cooling fan, rusted or water-damaged bearings will generate a whirring sound during rotation, especially during frequent summer usage. I also recommend checking refrigerant levels - insufficient refrigerant causing low pressure makes the compressor work under excessive load, resulting in harsher engine noise. All these issues relate to regular maintenance. Belts should be inspected every 2-3 years, otherwise minor problems escalate into costly repairs while compromising driving safety on the road.

[JessicaLynn]

My old car has been making annoying creaking noises whenever I turn on the AC recently. After taking it to the repair shop, I learned that the compressor bearing had loosened, causing severe vibration during operation which amplified the engine noise. They also explained that the drive belt had aged with cracks, and tightening when the AC is on resulted in harsh noises. Additionally, if the clutch mechanism gets stuck, it produces a popping sound, and failure to clean it promptly would lead to faster deterioration. This made me realize how costly it is to neglect regular inspections—for instance, the belt should be replaced every two years, and the compressor pressure needs frequent checks to ensure it's within the proper range. These are details easily overlooked but accumulate into expensive problems. Now, I've developed a habit: whenever I hear unusual noises, I immediately stop using the AC and investigate, to avoid sudden breakdowns during summer drives.

[IkerLee]

It's quite dangerous to ignore strange engine noises after turning on the car's AC. The core issue might be a loose or slipping belt - squealing sounds indicate excessive friction, which can cause wear on other components. The compressor itself can also produce humming noises when faulty, such as when internal parts wear out and compression efficiency declines. Problems with the fan system, like rusted fan shafts, can also make rotation sounds abnormal. These issues are all related to hot weather - frequent use makes breakdowns more likely. If ignored, the compressor might fail completely, leaving you without cool air while engine overheating could compromise driving safety. Therefore, it's recommended to seek professional repair immediately rather than attempting DIY fixes.