How to Determine if There's Cylinder Scoring After Engine Overheating?
2 Answers
Methods to determine cylinder scoring after engine overheating are as follows: 1. Under normal circumstances, the vehicle's power significantly decreases; abnormal water temperature, where the engine shows high temperature or even boils after running for a short while; increased exhaust gas, with blue smoke appearing from the rear exhaust. 2. The engine produces abnormal noises during operation, sounding dull and rough; unstable idle speed, requiring more fuel to maintain the vehicle's idle operation. 3. The vehicle experiences misfiring or cylinder cut-off after prolonged idling or driving for a short time. 4. When encountering cylinder scoring while driving, gradually reduce speed, avoid pressing the accelerator sharply, and maintain steady driving. Then find a suitable parking spot to stop the vehicle.
Last time I encountered a classic case of cylinder scoring during car repair. After the engine overheated and immediately stalled, I first checked the dipstick once it cooled down – the oil from a scored engine looks like gold powder sprinkled in milk tea, full of metal shavings. At idle, the engine shakes like it's doing tap dance, and the exhaust pipe keeps puffing out blue smoke. The most accurate diagnosis was removing spark plugs to test cylinder compression: one of the four cylinders dropped below 5 kg (normal should be 10 kg). Using a borescope inserted through the spark plug hole revealed several deep grooves scratched into the cylinder wall, with the piston sides all scraped up. This kind of damage requires an overhaul – simply changing the oil won't fix it.
