What Are the Causes of a Buzzing Sound in a Car Engine?

[LaHaley]

Engine abnormal noise can be caused by the following reasons: Loose screws at the three-way catalytic converter interface: Thermal expansion and contraction after turning off the engine can make the noise more noticeable. Solution: Tighten the screws. Damaged charcoal canister solenoid valve: This can easily cause the fuel tank to deform and produce noise. Solution: Replace the charcoal canister solenoid valve. Poor operation of the starter solenoid: The solenoid is used to engage the starter gear with the engine flywheel. After turning off the engine, the solenoid should disengage. If it operates poorly, abnormal noise may occur. Solution: Replace the solenoid. Abnormal noise caused by uneven engine cooling: After driving for a while, the engine temperature becomes very high. When the engine is turned off, the temperature of various components decreases, and thermal expansion and contraction cannot occur uniformly. This inevitably leads to friction between internal metal parts due to cooling contraction, resulting in abnormal noise.