What Causes Increased Engine Noise in Cars?

[StAriel]

Reasons for increased engine noise in cars: 1. Prolonged vehicle use leading to incomplete fuel combustion, resulting in carbon deposits in the engine; 2. Aging engine mounts, which normally absorb vibrations during engine operation; 3. Improper oil usage, such as using incorrect oil grades or mixing oils, causing viscosity mismatch and insufficient lubrication; 4. Abnormal cylinder operation evident through excessive exhaust pipe vibration; 5. Engine knocking caused by excessive carbon buildup or use of substandard fuel.