What is the reason for the increased noise after installing the engine guard plate?

[MacArcher]

After installing the engine guard plate, the increased noise is caused by friction between the plate and the moving parts outside the engine, resulting in abnormal sounds. Another situation is when the plate's vibration frequency is close to that of the car, leading to resonance. Precautions: Keep the engine compartment clean to prevent road water and dust from entering. Avoid sand, stones, and hard objects kicked up by the tires during driving from hitting the engine. While there may be no immediate impact on the engine, prolonged exposure can still affect it. Disadvantages: Hard engine guard plates may hinder the protective sinking of the engine during a collision, weakening this safety feature. Steel engine guard plates, made from ordinary steel and forcibly stretched using forming molds, typically weigh between 8-13 kg. They are installed with standard steel screws and feature a semi-enclosed design with openings for the oil filter, oil hole, and transmission oil hole. The lack of a thoughtful air vent design increases air turbulence in the engine compartment, raising wind resistance and noise. During driving, steel spacers and the steel guard plate can resonate, amplifying the noise.