What Causes the Engine Belt to Squeal When the AC is Turned On?
2 Answers
When the engine belt squeals upon turning on the AC, it is typically due to a loose or slipping compressor belt. Below are specific solutions: Solutions for AC belt noise: Turn on the AC and inspect whether the accessories driven by the belt have damaged bearings, are stuck, loose, or if the accessory power has increased. Consider replacing the belt or lightly sanding the contact surface between the pulley and belt with 100-grit sandpaper. Alternatively, you can apply 1-2 drops of engine oil to the contact surface between the belt and pulley to allow smoother operation. AC usage and maintenance: Select an appropriate AC temperature. In summer, many people prefer setting the temperature very low. However, excessively low temperatures can affect health, so it's important to adjust the temperature suitably. The most comfortable temperature range for humans is 20°C to 25°C. Above 28°C, people feel stuffy, while below 14°C, they feel cold. Therefore, the in-car temperature should be maintained between 18°C and 25°C. Excessively low temperatures can make people sick. In summer, avoid immediately switching to recirculation mode upon entering the car. Some drivers tend to turn on the AC and recirculation mode right after starting the car, thinking it cools the cabin faster. However, since the interior temperature is higher than outside, this approach is ineffective. Upon entering the car, first open the windows for ventilation and activate the external circulation to expel hot air. Once the cabin temperature drops, switch to recirculation mode.
As a long-time car maintenance enthusiast, I often encounter the issue of the belt making a screeching sound when the air conditioning is turned on. This is mainly because the compressor starting up increases the engine load, causing the belt to slip or become loose. The most common causes are belt aging, wear, or insufficient tension. During inspection, I can press the middle of the belt by hand; if the gap exceeds 1 cm, an adjustment is needed. If ignored, the belt may break, affecting the water pump or alternator, and even leading to the risk of a breakdown. It's recommended to regularly clean dust from the belt grooves, with replacement intervals typically every 3-5 years, depending on driving frequency. In short, maintaining a healthy belt system can enhance overall performance. It's best to seek a professional evaluation at a repair shop to prevent minor issues from escalating.
