What are the causes of engine bearing noise?
3 Answers
Engine bearing noise is caused by: 1. Excessive clearance between the piston and cylinder wall; 2. Over-tight assembly of the piston pin or connecting rod bearing; 3. Excessive clearance between the tappet and its guide hole; 4. Wear of the camshaft profile; 5. Loose starter claw causing pulley noise; 6. Severely loose connecting rod bearing cap bolts or melted/detached connecting rod bearing alloy. Solutions for engine abnormal noise include: 1. Check the fuel octane rating used; 2. Check engine temperature; 3. Check the air-fuel ratio of the engine mixture; 4. Check if the engine negative ground wire connection is good; 5. Check carbon deposits in the engine combustion chamber; 6. Check ignition timing.
I've always found the issue of engine bearing noise quite annoying, especially when suddenly hearing squeaking sounds while driving. Common causes are usually insufficient oil supply or dirty/degraded engine oil, resulting in inadequate lubrication of bearing components, which leads to dry friction between bearing shells and journal surfaces producing strange noises. Having driven for over a decade, I've encountered this situation myself - mainly due to frequent city traffic congestion where high engine loads cause oil temperature to rise and oil film breakdown. For prevention, I recommend regularly checking oil level and quality, changing oil every 5,000 to 7,500 kilometers, and using reputable synthetic oil brands to reduce impurities. If the oil pressure warning light comes on, it indicates insufficient oil pressure requiring immediate attention - otherwise severe bearing wear could lead to expensive engine repairs or even complete engine failure. Also avoid engine overheating or overloading during daily operation - proper maintenance can prevent 90% of such problems. In short, this noise serves as a warning - don't ignore it and get professional inspection early.
Last year, my car suddenly started making a metallic screeching noise. When I took it to the repair shop, the mechanic diagnosed an issue with the oil pressure system. He explained that the main causes were excessive wear on the bearing shells or deformation of the journal, likely due to my neglect of regular oil changes. Sludge buildup had clogged the oil passages, preventing lubrication from reaching the bearings. Another factor was the possible aging of the oil pump, causing delayed oil delivery and leading to localized dry friction. The repair wasn’t cheap—I spent a few thousand replacing parts. Now, I’ve developed the habit of checking the oil level with the dipstick after every refuel. This experience reminded me of the importance of regular maintenance, such as replacing the oil filter every two oil changes to ensure smooth oil flow. Delaying repairs only worsens the noise and drastically shortens the engine’s lifespan. If I hear any unusual sounds while driving, I stop immediately to inspect, avoiding bigger losses. Safety comes first—addressing issues early saves both hassle and money.
