What Causes Engine Belt Noise?
3 Answers
Engine belt noise is caused by belt looseness. In such cases, it is recommended to visit a repair shop to adjust the belt tension. Belt slippage produces a screeching sound, and the resulting friction-induced high temperatures further stretch the belt, worsening the slippage and creating a vicious cycle. Therefore, timely adjustment of belt tension is necessary. If the belt hasn't been replaced after nearly 20,000 kilometers of driving, it should be replaced directly. The timing belt is a crucial component of the engine's valve system, ensuring accurate intake and exhaust timing through its connection to the crankshaft and a specific transmission ratio. Belts are used instead of gears for transmission because they produce less noise, have minimal self-variation, and are easier to compensate for.
When I noticed unusual noises coming from the engine belt, my first thought was that the belt might be aged or worn out. Over time, the belt material can harden and crack, causing squeaking sounds during operation, just as commonly shared in car enthusiast groups. Additionally, a failing belt tensioner is a major issue; a loose spring can cause the belt to slip, creating friction noises, which are more noticeable in hot weather. Furthermore, unstable operation of accessories like the alternator or water pump can also transmit abnormal sounds to the belt. If not addressed promptly, not only will the noise be annoying, but it can also wear out other components, such as causing the engine to overheat and compromising driving safety. It's recommended to visit a repair shop as soon as possible to check if a new belt is needed or if the tension needs adjustment. Personally, I perform a simple inspection of the belt condition every six months to prevent small issues from turning into major problems.
When I hear that rattling or screeching noise while driving, my first thought is that the engine belt is acting up. The most common causes are a loose belt, a faulty tensioner, or a dirty surface where dust buildup causes it to slip. Especially in rainy or humid conditions, the belt slipping noise becomes louder—just like what happened with my old car last year, which later needed re-tightening. Additionally, after years of use, the rubber in the belt naturally hardens and cracks, which can also cause unusual noises. If the associated bearings, such as those in the air conditioning compressor, have issues, they can also make the belt noisy. Never ignore these sounds, as the risk of belt failure increases, potentially leaving your car stranded on the roadside. Visit a reliable repair shop early for diagnosis and ensure the right type of belt is replaced for peace of mind in daily driving.
