What Causes the Engine Noise to Increase After Maintenance?
2 Answers
Reasons for increased engine noise after maintenance: 1. Overfilled engine oil: In fact, it's common for engine noise to increase after an oil change, possibly due to overfilled engine oil. Excessive oil increases crankshaft rotation resistance, reduces engine power, alters the air-fuel ratio in the combustion chamber, and raises the likelihood of knocking, resulting in louder noise. 2. Inappropriate oil viscosity: When new oil is added, the engine may need time to adapt to its viscosity, potentially causing higher RPMs and consequently louder engine noise. This usually normalizes after a break-in period. Additionally, the issue might stem from using oil with incorrect viscosity. If the oil viscosity is too low, insufficient lubrication leads to increased wear and noise from engine components. Conversely, if the viscosity is too high, it places excessive load on the engine, also generating noise.
After maintenance, the engine noise became louder. Based on my driving experience, it might be due to incorrect oil level adjustment during the oil change—too much or too little oil can increase friction and make the noise louder. Also, if the air filter is not installed properly, it can cause a hissing sound due to poor air intake. If the belt is loose, it will squeak during operation. I recommend checking the oil dipstick first—the level should be between the high and low marks. Don’t overlook these small details; promptly return to the maintenance shop for a recheck to prevent part damage. If the engine abnormal noise persists, it could lead to part failure, so don’t delay.
