What are the symptoms of engine cylinder scuffing?
4 Answers
Engine cylinder scuffing manifests through the following symptoms: abnormal engine operation, difficulty in vehicle acceleration, sudden rise in engine coolant temperature, excessive thermal expansion of engine pistons, piston rings, and cylinder block, insufficient clearance between cylinder and piston, and piston seizure within the cylinder. Cylinder scuffing is one of the common failures in automotive engines, referring to deep grooves being formed on the cylinder wall, which leads to loss of sealing between the piston, piston rings, and cylinder wall during friction, resulting in reduced cylinder compression pressure and loss of power. An engine is a machine capable of converting other forms of energy into mechanical energy, including internal combustion engines (reciprocating piston engines), external combustion engines (such as Stirling engines, steam engines, etc.), jet engines, electric motors, among others.
I once encountered a car with cylinder scoring, and the engine noise was particularly loud. During cold starts, you could hear a knocking sound similar to banging on a water bucket, and when the accelerator was pressed hard, it turned into a screeching metal friction noise. At idle, the car shook violently, and even the steering wheel vibrated. The most obvious symptom was a sudden loss of power—when climbing a slope, even with the accelerator floored, the speed wouldn't increase, and blue smoke with a burnt smell came from the exhaust. In severe cases of cylinder scoring, after parking and opening the hood, you could smell a sour odor of burnt engine oil, and pulling out the dipstick would reveal a lot of metal shavings. In such a situation, you should immediately turn off the engine and call a tow truck—continuing to drive could completely wreck the engine.
The engine sounds completely off after cylinder scoring. At startup, it makes a clanging noise like hitting an iron bucket, with sharp and crisp tapping sounds. When revving above 3000 RPM, the noise turns into a harsh metallic scraping sound that sends shivers down your spine. The exhaust pipe first emits light blue smoke, then it thickens, resembling burning plastic. The most frustrating part is the severe power loss—even with the tachometer showing 4000 RPM, the car accelerates as slowly as a snail climbing a hill. The oil consumption is alarmingly high, with the dipstick showing no oil in less than a week. Don't push it further—driving even 10 more kilometers could completely ruin the engine block.
There are three particularly obvious symptoms of engine cylinder scoring: First, there is a metallic abnormal noise, which sounds like hammering the cylinder block at idle speed; second, there is severe oil burning, with the exhaust pipe continuously emitting blue smoke or even sparks; third, there is a cliff-like drop in power, where stepping hard on the accelerator causes the RPM to soar but the vehicle speed does not increase. The dashboard often shows a constant water temperature warning light, and the radiator fan spins wildly without stopping. Checking the engine oil will reveal sludge mixed with aluminum shavings, and opening the oil filter can pour out metal fragments. When these signals appear, you must immediately stop the car and call for rescue.
