Is It a Serious Problem to Have Engine Oil on Spark Plugs?
2 Answers
Excessive engine oil inside the spark plugs can affect ignition and sometimes cause misfires. Where Are Spark Plugs Located: Spark plugs are installed on the side or top of the engine. In earlier models, spark plugs were connected to the distributor via ignition cables. Over the past decade, most car engines have been updated to feature direct connections between the ignition coils and spark plugs. How Spark Plugs Work: Under high voltage, the air between the center electrode and the side electrode of a 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. A discharge channel forms in the gap, resulting in a "breakdown" phenomenon. At this point, the gas becomes a luminous body, known as a "spark." Along with thermal expansion, a "snapping" sound is also produced. The temperature of this electric spark can reach 2000-3000°C, which is sufficient to ignite the air-fuel mixture in the engine's combustion chamber.
Oil on spark plugs is a serious issue, and I've seen it quite often. In most cases, it's due to a faulty valve cover gasket seal, allowing oil to seep in and contaminate the spark plugs, leading to ignition difficulties, severe engine shaking, and potentially a spike in fuel consumption. If left unattended, the spark plugs can burn out, damaging the ignition coils as well, resulting in costly and time-consuming repairs. During inspection, you can spot oil stains by removing the spark plugs or checking for oil leaks nearby. Head to a repair shop immediately to replace the gasket and clean the area—delaying could cause further engine damage. Regular maintenance checks can help avoid unnecessary expenses.
