Why Do Engine Bearings Get Damaged?
2 Answers
Reasons for engine bearing damage: 1. Damage caused by prolonged idling. When the engine idles for too long, it operates below normal working temperature. Incomplete combustion of fuel injected into the combustion chamber causes some unburned fuel to flow down the cylinder walls into the crankcase, breaking down the oil film and reducing lubrication effectiveness. 2. Damage caused by shutting down the engine immediately after prolonged operation. After extended high-load operation, internal engine components reach peak temperatures, especially in the combustion chamber. When the engine is turned off, both the cooling and lubrication systems stop working, trapping heat and causing temperature spikes that break down oil films on lubricated surfaces. 3. Damage from immediately operating at high speeds and full load after startup. Engaging in high-speed operation and full-load work without proper warm-up causes problems because the engine hasn't reached optimal operating temperature. Contact surfaces and clearances aren't properly seated, and cold oil's poor flow characteristics prevent proper heat dissipation from moving parts. 4. Damage from incorrect adjustments or operation. Improper crankshaft end play (either excessive or insufficient) leads to thrust bearing failure. Excessive clearance causes impact damage, while insufficient clearance leads to overheating and abnormal wear, particularly damaging the seventh main bearing. 5. Installation errors causing bearing damage. Connecting rod deformation beyond specifications, uneven tightening of bearing cap bolts, accidental damage to bearing backs during installation, or incorrect bearing positioning can all lead to premature bearing failure.
I remember one time when I was driving, the engine suddenly made an unusual noise. After taking it to the repair shop, I found out the bearing shells were worn out. Bearing shells are mainly a supporting component in a car's engine, helping to reduce friction on the crankshaft. The most common cause of damage is lubrication issues, such as insufficient engine oil or poor oil quality from not changing it for too long, leaving the bearing shell surface unprotected and causing direct metal friction that leads to failure. Driving habits also play a role; frequently driving at high speeds or carrying heavy loads uphill puts more strain on the engine, raising oil temperatures and causing the oil film to break down faster. Foreign particles entering the engine oil are another risk, like dust not being cleaned properly during maintenance or metal shavings from aging piston rings scratching the bearing shell surface. For prevention, I’ve made it a habit to change my full synthetic oil every 5,000 kilometers, check the oil pressure gauge and filter, and avoid steep slopes and sudden acceleration. Replacing bearing shells is quite expensive, so regular maintenance saves both hassle and money.
