What are the causes of excessive engine noise?

[Kaden]

There are two fundamental reasons for excessive engine noise: excessive engine carbon buildup and the use of inappropriate or dirty engine oil. Poor oil quality: On one hand, if the viscosity of the car's engine oil does not match the engine, it can easily lead to carbon buildup, causing the engine noise to increase. On the other hand, if the oil viscosity is too low, it can result in insufficient lubrication, leading to wear on engine components, abnormal noises, and reduced car power. Engine misfire: Engine misfire mainly refers to one or more cylinders in the engine not functioning properly. Common symptoms include reduced car power, intermittent exhaust gas flow, severe shaking of the exhaust pipe, and clearly audible abnormal engine noises like "popping" or "thumping." Engine carbon buildup: Carbon buildup includes cylinder carbon buildup, throttle carbon buildup, spark plug carbon buildup, and intake pipe carbon buildup. When there is excessive carbon buildup inside the engine, the car's ignition energy, intake efficiency, and air-fuel mixture ratio are affected, leading to unstable power output, shaking during idling and acceleration, and excessive engine noise.

[LeLogan]

The engine noise was loud, and I encountered it once while driving, with a buzzing sound like a tractor. Possible causes include worn bearings, which support the rotating parts inside the engine—when they wear out, they can produce a squealing noise; piston issues leading to knocking sounds; leaks in the exhaust system, where a hole in the muffler can cause a popping noise; loose or aged belts, resulting in a hissing sound; insufficient or low-quality engine oil, increasing friction and noise significantly; or even worn engine mounts, which can amplify vibrations and noise. That time, the noise grew louder during a long drive, so I promptly went to a repair shop for inspection—replacing a bearing made it quiet again. It's advised not to ignore unusual noises, as they may indicate underlying issues. Regularly checking the oil and belts can help prevent problems. If you encounter noise while driving, slow down, pull over safely, and address it promptly to avoid costlier repairs later.

[DelEleanor]

I often work on cars for fun, and when the engine noise is loud, I take it apart to find the source. Bearings are a common issue—when worn, they produce loud friction sounds during rotation. A leak in the exhaust system can be particularly noisy, with a punctured muffler being the main culprit. Loose or worn belts create noticeable noise at high RPMs. Faulty valves or piston rings may cause rhythmic knocking. Low or dirty engine oil with insufficient viscosity can increase noise. A malfunctioning fan or water pump might also contribute. For diagnosis, I record the noise with my phone—different sounds correspond to different parts: squeaking may indicate bearings, while popping suggests exhaust issues. DIY fixes like tightening belts or adding oil can help. However, for complex problems like replacing bearings, it's safer to consult a professional. Regular maintenance, such as checking exhaust joints and belts, can minimize noise issues.

[DylanRose]

Excessive engine noise is often related to component aging. Worn-out bearings cause continuous rattling; exhaust leaks amplify the sound; loose belts create screeching noises; insufficient engine oil increases friction and noise. After decades of driving, I've found that noise frequently stems from inadequate maintenance, such as not changing the oil on time. For safety, pull over and inspect when hearing unusual sounds—don't force the engine. Simple fixes like topping up engine oil can reduce noise.