What Causes the Squeaking Sound in Cars on Rainy Days?
3 Answers
On rainy days, the squeaking sound in cars is caused by the smooth wear of the contact surface between the belt and the pulley. Below is relevant information about pulleys: 1. Introduction: A pulley, belonging to the category of hub-type components, generally has relatively large dimensions and is primarily manufactured through casting or forging processes. 2. Applications: Pulleys are mainly used for long-distance power transmission, such as power output in small diesel engines, agricultural vehicles, tractors, automobiles, mining machinery, machining equipment, textile machinery, packaging machinery, lathes, forging machines, power transmission in small horsepower motorcycles, power transmission in agricultural machinery, air compressors, reducers, speed reducers, generators, cotton gins, etc.
Last time at the repair shop, there was an owner really worried about the squeaking noise on rainy days. Most of the time, it's an issue with the brake pads and rotors. Rain causes the rotor surface to rust, and when you hit the brakes in the morning, the metal grinding against the rust layer makes that squeaking sound. It usually quiets down after a few minutes of driving once the rust wears off. Another less common but often overlooked reason is the belt! A wet alternator belt gets slippery, and when the rubber slips against the metal pulley, it produces a sharp noise. Check if the belt is aged or cracked. If the noise gets worse when turning, it might be due to lack of lubrication in the steering ball joint—rainwater dilutes the grease, leading to dry metal friction. For noises under the car, check the exhaust pipe hanger; the rubber part can creak in the rain when it's aged.
This morning when I opened the car window in the rain, I heard a squeaking sound from under the car, like nails scratching a blackboard. My mechanic friend taught me to identify the issue by location: if there's rhythmic chirping near the wheels, it's likely small stones stuck in the brake pads or rust; continuous high-pitched screeching usually means a loose belt. Last week, my neighbor's car made noise when it rained, and it turned out to be a deformed heat shield on the exhaust pipe vibrating when hit by raindrops. I remember one time my car would squeak whenever I turned left - the mechanic said the lower control arm rubber bushing had cracked and let water in, causing metal-on-metal friction after lubrication failed. Replacing the rubber bushing only cost 80 yuan. Don't ignore strange noises after rain - water-soaked rubber parts accelerate aging, which is the most troublesome issue.
