What are the classifications of car noise?

[Parra]

Car noise can be classified into engine noise, tire noise, wind noise, and chassis noise. Below are detailed explanations and solutions for each: Engine Noise: If the engine noise is noticeable when the car is cold but disappears after warming up, it is likely because the car has been parked for a long time, causing the lubricating oil to flow back into the oil pan. During a cold start, the oil pump cannot immediately establish oil pressure, preventing the formation of an oil film between components. This is especially true for the valves in the cylinder head (upper part), which do not receive lubrication during a cold start. Whether it's hydraulic lifters or mechanical rocker arms, there will be some valve clearance, or the timing chain may not function properly due to insufficient oil pressure, leading to a ticking sound. In such cases, it is advisable to visit a repair shop promptly. Tire Noise: All vehicles have tire noise, though the level varies. Tire noise is generally caused by air flow through the gaps in the tire tread, creating air noise. Since tires are made of rubber, they tend to harden and age over time, leading to increased noise. New tires, with their better elasticity, perform well in terms of both noise reduction and comfort. If the tire noise is excessive, check if the tires have aged and consider replacing them if necessary. Wind Noise: Like tire noise, all vehicles experience wind noise, but it can be categorized into several types. One type is caused by pressure changes due to airflow separation around the vehicle body. Another is wind leakage or suction noise, which occurs when air is drawn into the cabin and body gaps, interacting with the surrounding airflow. The third type includes other noises, such as cavity resonance. Wind noise increases with higher driving speeds, so reducing speed appropriately can help mitigate it. Chassis Noise: This is typically due to issues with the shock absorbers. When the entire vehicle produces loud noises while driving over uneven surfaces, it's essential to inspect the shock absorbers, as severe oil leakage may be the cause.