What are the symptoms of engine cylinder scoring?

[SanAdam]

Engine cylinder scoring manifests as: deep grooves being formed on the cylinder wall, loss of sealing between the piston, piston rings and cylinder wall during friction, resulting in reduced cylinder compression pressure and loss of power. Under these conditions, the engine will produce abnormal noises, its output power will rapidly decline, and severe oil burning will occur with blue smoke, potentially even leading to crankcase explosion. To determine whether cylinder scoring has occurred, pay attention during driving for symptoms such as abnormal engine noises, power loss, exhaust emissions (known as 'blow-by'), excessive fuel consumption, difficulty maintaining idle, and hard starting after shutdown. Generally, if abnormal engine noises are detected while driving, the engine should be shut off immediately because continued operation may worsen cylinder wall damage.