What Causes a Large Amount of Engine Oil in the Spark Plug?

[Landon]

Spark plugs containing a large amount of engine oil are caused by a malfunctioning forced ventilation valve in the crankshaft case, cylinder wall scoring, or severe piston ring wear leading to oil leakage. How Spark Plugs Work: Under high voltage, the air between the center electrode and the side electrode of the spark plug rapidly ionizes, forming positively charged ions and negatively charged free electrons. When the voltage between the electrodes reaches a certain level, the number of ions and electrons in the gas increases like an avalanche, causing the air to lose its insulating properties and forming a discharge channel, resulting in a "breakdown" phenomenon. At this point, the gas becomes a luminous body, known as a "spark." Along with thermal expansion, a "crackling" sound is also produced. The temperature of this electric spark can reach as high as 2000-3000°C, sufficient to ignite the air-fuel mixture in the combustion chamber. Criteria for Determining Spark Plug Damage: Damaged spark plugs can exhibit the following symptoms: difficulty starting, reduced power, excessive exhaust emissions, and increased fuel consumption.