What Causes the Buzzing Sound After Starting the Car?

[Campbell]

Possible reasons for the buzzing sound in the vehicle include: uneven tire tread blocks or severe wear; imminent damage to the wheel hubs of certain wheels, with the most direct symptom of hub failure being an increase in the buzzing sound as the vehicle speed rises, which then maintains a constant volume after reaching a certain speed. Here is additional information: 1. Requirements for interior noise: According to the "Technical Conditions for Motor Vehicle Operation Safety" issued and implemented by the former National Technical Supervision Bureau on January 1, 1998, the interior noise level of passenger vehicles should not exceed 82 decibels; the noise level near the driver's ear should not exceed 90 decibels. Interior noise levels below 60 decibels are generally acceptable, while 40-60 decibels represent normal conversation levels. 2. Sources of interior noise: a. The vehicle's engine is a source of noise, which can be generated and transmitted through the front fenders, hood, firewall, and exhaust pipe. b. Road noise is produced when the vehicle is driven at high speeds, caused by wind cutting in and vibrations from the chassis, as well as the impact of sand and gravel on the road against the vehicle's chassis.