What are the symptoms of diesel engine cylinder scuffing?
2 Answers
Diesel engine cylinder scuffing, also known as cylinder dragging. The intuitive phenomenon is that obvious dragging marks can be seen on the surface of the cylinder, and the piston's cylindrical surface also shows accompanying marks. The symptoms reflected in the working state include reduced output power, increased fuel consumption, and even affecting exhaust emissions to fail to meet standards. In severe cases, it may render the diesel engine inoperable. The reasons are as follows: 1. Improper assembly during overhaul causing cylinder scuffing: The vehicle engine and its combined components are very precisely matched. Any improper assembly or coordination of parts (including piston rings and cylinder liners) during disassembly and overhaul, or prolonged high-speed or overload operation of the engine without proper running-in after overhaul, can cause engine failures, such as cylinder scuffing. 2. Poor filter; it can easily cause excessive wear of the engine and even lead to cylinder scuffing accidents. The reason is that dust in the air can pass through a poor air filter into the combustion chamber and be brought into the crankcase by the reciprocating motion of the piston, mixing with the lubricating oil. The dust mainly contains silicon compounds, and the hardness of silicon compounds is greater than that of cast iron or steel piston rings and cylinder liners, thus causing cylinder scuffing. Therefore, dust is very harmful to the engine, and many vehicles in China undergo engine overhauls every year due to such failures. 3. Poor quality of lubricating oil: Under normal circumstances, if the lubricating oil quality is poor, the possibility of bearing failure is higher than that of cylinder scuffing occurring earlier. This is because the working conditions of the bearings are more demanding and require high-quality oil to ensure lubrication; while the material of the cylinder liner is better, unless under special circumstances, cylinder scuffing accidents usually do not occur first. Cylinder scuffing accidents can be caused by mechanical failures or lubrication system failures, but have less to do with the quality of the oil. The key lies in how to maintain and use the engine properly in daily life.
When I used to drive a diesel truck, I encountered cylinder scuffing issues. The most noticeable symptom was a continuous metal scraping sound from the engine, especially during acceleration or uphill driving, resembling a creaking grinding noise, which indicated scratches on the cylinder walls. Power output would drop sharply—stepping on the gas felt like the truck couldn’t move, struggling particularly on inclines with sluggish acceleration, crawling like a snail. Additionally, the exhaust pipe started emitting blue smoke, sometimes mixed with black smoke, signaling oil leakage into the combustion chamber and incomplete burning. Oil consumption was much faster than normal, requiring frequent checks of the dipstick, sometimes needing a top-up every two or three days. During cold starts, the engine often failed to ignite or shook violently after starting, affecting driving stability. If left unaddressed, compression pressure would keep dropping, eventually causing the engine to stall, posing safety risks. I always remind other drivers to stop and inspect at the first sign of unusual noises to prevent minor issues from escalating.
