What Causes the Abnormal Noise When Starting a Car?

[SanAshley]

There can be multiple possibilities for abnormal noises in the engine compartment. Engine noises indicate that the technical state of a certain mechanism in the engine has changed, primarily due to excessive wear of some parts or improper assembly and adjustment. Some noises may even signal potential catastrophic damage to the engine. Therefore, when abnormal noises occur in the engine, timely repairs are necessary to prevent further damage. If the noise originates from inside the engine, most car owners cannot resolve it themselves, and it is best to send the vehicle to a professional repair shop. Here is some additional information: 1. Transmission Abnormal Noise: If there is a "rustling" sound inside the transmission while driving, which disappears when the clutch or accelerator is pressed, and a whistling-like sound occurs during gear shifting, it may indicate transmission issues. The transmission has many components, and the causes of noise are complex. When analyzing and diagnosing, pay attention to whether the noise is related to specific speeds or certain gears. This is crucial for identifying transmission faults. If a particular gear produces noise, it is likely related to the components affecting that gear's transmission. If all gears produce noise, it often indicates a fault in the constant-mesh gear shaft or insufficient transmission oil. Also, observe whether the noise is related to specific actions, such as shifting gears, starting, rapid acceleration, sudden deceleration, or turning. These actions are effective indicators for diagnosing abnormal noises, with speed and direction changes being particularly important for identifying rear axle issues. If the transmission noise is significant, it is advisable to send the vehicle to a professional repair shop to identify and replace the faulty components. 2. Wear-Related Abnormal Noise: When pressing the accelerator or brake while driving, there may be some minor noises from certain parts of the car body. These sounds are not loud and do not affect normal driving, but they can raise concerns about potential faults. Door noises are mainly caused by insufficient lubrication. It is important to determine whether the noise comes from the door hinges or internal components like the window regulator, door lock mechanism, or handle mechanism. For door hinges or limiters, specialized door hinge and track grease should be used. For internal components like the window regulator, door lock mechanism, or handle mechanism, specialized door accessory grease is recommended.