What Causes Engine Bearing Noise?

[Isaac]

Engine bearing noise is caused by abnormalities in the crankshaft or connecting rod bearings, or a lack of lubrication. Below are detailed explanations of the causes: Abnormalities in Crankshaft or Connecting Rod Bearings: The cause of engine bearing noise is abnormalities in the crankshaft or connecting rod bearings. In such cases, it is best to immediately stop the engine, call for assistance, and proceed to a 4S shop for inspection and repair. Lack of Lubrication: Engine bearing seizure occurs when the crankshaft or connecting rod bearings experience sintering due to insufficient lubrication or excessive heat wear. This can lead to the crankshaft seizing and forcibly stalling the engine. In severe cases, it may even damage the crankshaft bearing seat, resulting in the complete scrapping of the engine assembly.

[GabriellaDella]

After running an auto repair shop for so many years, I've seen plenty of engine noises. The most common is piston ring wear—due to prolonged high-temperature operation, friction between the piston and cylinder wall creates a metallic knocking sound. Worn crankshaft or connecting rod bearings can also cause noise, especially noticeable at high RPMs, often due to insufficient lubrication or degraded oil. A loose timing chain is another culprit; when stretched, it produces a rattling sound. Excessive valve clearance also leads to noise, typically audible at idle. I recommend checking oil level and quality, with regular oil changes for prevention. If the noise persists, get it diagnosed at a professional shop immediately—don't wait until the engine fails. Cold-start noises are especially concerning, as poor oil flow worsens wear.

[Evie]

When I work on car modifications myself, engine noises always take up a lot of my time. I often encounter bearing issues, such as wear on the crankshaft or connecting rod bearings, which produce a sound like metal grinding, usually caused by dirty or insufficient oil. Incorrect valve clearance can create a tapping noise, especially noticeable during acceleration. A loose timing chain makes a rhythmic sound, like a clock ticking. During DIY inspections, I first listen for the noise source—bottom noises might indicate an oil pan leak, while top noises involve the valves. Checking oil pressure is also crucial; low pressure suggests lubrication failure. Replacing bearings or adjusting clearance can solve the problem, but for complex issues, consulting an expert is more efficient. Regular maintenance with high-quality oil helps prevent recurring noises.

[DelFinley]

When I first started learning to drive, the sound of the engine would always make me nervous. It might be due to worn piston rings, causing friction against the cylinder walls as the pistons move up and down. Excessive valve clearance can also produce a ticking sound, especially noticeable at idle. A friend mentioned that a loose timing chain could create similar noises. If the bearings are damaged, the metallic sound can be quite harsh. It's best not to attempt repairs yourself—instead, pull over safely and check the engine oil. If the oil level is low or dirty, top it up first. However, in most cases, it's better to visit a repair shop and let a mechanic diagnose the issue with proper tools. Safety comes first—ignoring unusual noises could lead to a breakdown, especially during long trips.