What Are the Main Reasons for Loud Engine Noise in Vehicles?
2 Answers
Vehicle engine noise can be attributed to several main factors, including carbon buildup, poor sound insulation, low coolant temperature, shock absorber issues, or engine knocking/detonation. Carbon Buildup: As engine oil becomes thinner with use, carbon deposits accumulate more easily. Thinner oil can lead to oil leakage, exacerbating carbon buildup and resulting in significant power loss. When new oil is added, the engine may struggle to adapt to the oil's viscosity, potentially causing higher RPMs and increased engine noise. It is recommended that owners clean carbon deposits promptly. Poor Sound Insulation: If the engine sounds normal from outside the vehicle but seems excessively loud inside, this indicates poor sound insulation. Owners should inspect the vehicle's sealing strips for signs of aging or consider enhancing the vehicle's sealing effectiveness before reassessing the noise level. Low Coolant Temperature: When the coolant temperature is too low, issues can arise, and engine noise may increase. It is advisable to check and replace the coolant to prevent further complications. Shock Absorber Issues: The condition of the vehicle's shock absorbers can usually be assessed when driving over speed bumps. If the shock absorbers are faulty, they can contribute to increased engine noise. In such cases, replacing the shock absorbers promptly is recommended. Engine Knocking/Detonation: Knocking occurs when, after the spark plug ignites, the remaining air-fuel mixture spontaneously combusts. This creates opposing flame fronts—one from the spark plug and another from the spontaneous combustion—which propagate at high speeds, producing a sharp knocking sound and increasing engine noise. Owners should inspect and replace spark plugs as needed.
Recently, my old car's engine has become unusually noisy, and upon careful consideration, there might be several common reasons. First, internal engine wear, such as loose piston rings or bearings, can cause metal friction sounds after prolonged use. Second, issues with the exhaust system, like an aging muffler or leaking pipes, can result in a whooshing noise from escaping air. Additionally, insufficient or dirty engine oil fails to provide proper lubrication, leading to abnormal sounds during operation. Sometimes, a loose belt or a faulty ignition coil can also increase noise levels. I recommend visiting a professional auto repair shop as soon as possible for a thorough inspection, especially to identify the noise source: if it's coming from the engine compartment, it's likely a mechanical issue; if it's from the exhaust pipe, the muffler might need replacement. Ignoring this problem long-term could lead to premature vehicle failure, so addressing it early is more cost-effective.
