What Causes the Abnormal Noise When Accelerating Between 1800 to 2000 RPM?
1 Answers
The abnormal noise occurring at 1800-2000 RPM is primarily caused by low engine oil viscosity. Other potential causes include severe wear of hydraulic lifters over time, aging of engine peripheral components, or excessive valve clearance. For noises specifically at 2000 RPM, checking valve clearance is recommended. Causes of abnormal noise after cold starts include: 1. Slipping alternator belt: Intense friction between the loose belt and pulley generates vibration and characteristic noise. Belt slippage often indicates looseness requiring immediate inspection at a repair shop. 2. Valve train noise: After prolonged parking, engine oil drains to the bottom, leaving the valve chamber inadequately lubricated. The absence of oil's sealing and lubricating properties on valves results in pronounced noise during morning startups.