What are the symptoms of a bad engine bearing?
2 Answers
Engine bearing failure exhibits noticeable symptoms such as bearing noise and bearing seizure due to dry friction. The details are as follows: Noticeable bearing noise: During cold starts under heavy load, the engine oil, being viscous at low temperatures, fails to lubricate the bearings in time. Meanwhile, the bearing surface reaches an instant high temperature due to the heavy load, causing metal fusion and seizure. Over time, as normal wear increases, the bearing clearance expands, leading to noticeable bearing noise. This results in oil loss and pressure drop, insufficient oil supply between bearings, high temperatures, and eventual fusion and seizure. Bearing seizure due to dry friction: Lack of coolant or prolonged high-temperature driving causes the engine oil temperature to rise rapidly, losing its viscosity. This prevents the formation of a protective oil film between the shaft and bearing, leading to severe friction, fusion, and seizure. Reduced oil pump pressure makes it difficult for the oil to reach designated lubrication points at standard pressure. Clogged oil screens or passages by contaminants block oil flow to the crankshaft, and oil leaks in the pipeline reduce lubrication system pressure, resulting in bearing seizure due to dry friction.
When driving, if the engine bearings fail, meaning there's an issue with the bearings, you'll first hear strange metallic knocking or grinding noises from the engine, especially during startup or when accelerating by pressing the gas pedal. The car will then start shaking violently, with the steering wheel wobbling and noticeable vibrations on the dashboard. The oil warning light often comes on, indicating low pressure due to oil leakage from worn components. I experienced this once on the highway—the noise suddenly got louder, and the shaking intensified, scaring me into pulling over immediately to check, only to find the oil pressure had dropped to dangerous levels. Any later, and the engine could have been ruined. This usually stems from old or poor-quality oil maintenance. It's best to change the oil regularly and head straight to the shop if you hear unusual noises—don't wait until the whole engine gives out.
