What Causes the Buzzing and Resonance in a Prado?
2 Answers
Reasons for resonance and noise during car braking are as follows: 1. Tensioner pulley wear: The tensioner pulley's function is to tighten the engine belt, preventing the generator and power steering pump from slipping. Due to prolonged pressure and high-speed rotation, the bearings inside the tensioner pulley are prone to wear, resulting in noise and resonance. If the buzzing and resonance are confirmed to be caused by the tensioner pulley, it is also necessary to check the engine mounts, as their role is to reduce vibrations and noise generated by the engine. 2. Exhaust pipe deformation: In most front-engine models, the exhaust pipe extends from the undercarriage to the rear of the vehicle. Driving on rough roads or impacts to the chassis can easily cause the exhaust pipe to dent or deform. A deformed exhaust pipe increases exhaust resistance, leading to buzzing and resonance sensations from the exhaust system.
My Prado used to produce a humming resonance noise at around 60 mph. The mechanic found that the driveshaft universal joint was dry due to lack of grease. This vehicle often drives on rough roads, and the cracked driveshaft seal wasn't detected in time, causing all the grease to leak out. After the bearing balls wore out, the gap increased, resulting in a humming noise and steering wheel vibration when rotating. Another common issue is the aging of the right engine mount rubber. Once the rubber cracks, the damping fails, and you can feel seat vibrations even at idle. If new tires are installed without dynamic balancing, wheel hopping at high speeds can also cause humming noises. It's recommended to focus on inspecting the drivetrain and suspension components, as problems in these areas are most likely to cause resonance.
