What Causes Increased Engine Noise After Maintenance?
2 Answers
Reasons for increased engine noise after maintenance: 1. Using engine oil of different brands or specifications may cause louder operation; 2. Prolonged lack of maintenance leads to excessive carbon buildup. After maintenance with fresh oil replacement, the engine operates with greater resistance in a carbon-rich environment, resulting in increased noise; 3. Mixing new and old engine oils, especially when they are of different brands or specifications, will amplify engine noise. The automobile engine is the device that provides power to the vehicle, determining its power performance, fuel economy, stability, and environmental friendliness. Depending on the power source, automotive engines can be categorized into diesel engines, gasoline engines, electric vehicle motors, and hybrid powertrains.
As a seasoned car enthusiast who often tinkers with vehicles, I find it quite common for the engine noise to increase after maintenance. Engine oil is the prime suspect – if the wrong viscosity is used (e.g., 10W-40 instead of 5W-30), increased friction leads to louder noise; overfilling beyond the max level raises oil pressure, causing abnormal sounds; underfilling results in insufficient lubrication and component wear noise. New oil typically needs 100-200 km to break in and smooth out. Additionally, a loosely installed air filter or improperly sealed gasket disrupts airflow, making the engine work harder and louder. Incorrectly gapped new spark plugs cause ignition timing deviations, increasing vibration and noise. Loose bolts (e.g., belt tensioner) during maintenance create noticeable rattling. My advice: first check the dipstick to ensure oil level is midway, then observe during break-in. Persistent noise warrants a garage inspection of the belt system and voltage regulator to prevent engine damage – minor repairs now beat major overhauls later. Regular maintenance with correct parts avoids this hassle.
