What Causes Cylinder Scoring While Driving?

[MilaLee]

Here is a detailed explanation about cylinder scoring: 1. Definition: Cylinder scoring is a technical term used by maintenance personnel. It refers to deep grooves being formed on the inner wall of the cylinder, causing the piston, piston rings, and cylinder wall to lose their sealing ability during friction. This results in reduced cylinder compression pressure and loss of power. This phenomenon is also one of the common engine failures. 2. Causes: Engine cylinder scoring is a relatively serious issue, and there are many reasons that can lead to this phenomenon. It is generally related to the piston assembly, cylinder liner, and daily driving habits. In older vehicles, the piston ring gap will inevitably change. If the gap is too large or too small, or if the rings expand and deform, they can damage the cylinder wall. Excessive carbon buildup on the piston rings can also cause this issue.

[Cox]

I'm absolutely qualified to speak on this, having repaired cars for nearly 20 years. The common causes of cylinder scoring are basically those few. The most critical issue is engine oil problems—either failing to top up when oil is low or using counterfeit/inferior oil. Once the lubricating oil film breaks, pistons and cylinder walls grind directly against each other. Then there's inadequate cooling—clogged radiators or failed fans causing engine overheating, where metal expands and seizes. Another cause is prolonged aggressive driving, especially stomping the accelerator during cold starts, creating uneven expansion between pistons and cylinder liners. Last time, an owner who hadn't checked the dipstick for 5,000km scored three deep grooves in his cylinders.

[HavenAnn]

From a technical perspective, the core issue of cylinder scuffing lies in abnormal contact between the piston and cylinder wall. There are three primary causes: First, lubrication failure, including oil pump malfunction leading to low oil pressure, clogged oil passages, or using incorrect oil viscosity. Second, excessive thermal load, where cooling system failure causes cylinder liner temperature to exceed 250°C, breaking down the oil film, while cast iron liners expand less than aluminum pistons. Third, mechanical damage, such as cylinder liner deformation or piston ring fracture and sticking. Special attention should be paid to poor intake system sealing allowing dust ingress, causing abrasive wear. Such problems are often accompanied by sudden coolant temperature rise or oil pressure warnings.

[OLillian]

Have you ever seen a scored piston? There's one hanging in my workshop. A common mistake beginners make is insufficient warm-up time in winter when the oil has poor fluidity at cold temperatures, leading to localized lubrication failure. Another issue is installing a turbo without reinforcing the cylinder block - the liners can't withstand the high pressure and temperature. Once I handled a car where the owner used cheap, low-quality gasoline causing severe knocking that deformed the piston. Actually, many modern cars have oil monitoring systems - never ignore that warning light. Also, frequent short trips cause heavy carbon buildup, and scratched cylinder walls become another hidden danger.