What Causes Oil on Spark Plugs?
2 Answers
The causes of oil on spark plugs: The valve cover gasket has aged, and this component is responsible for sealing the engine lubricating oil. When it ages, lubricating oil naturally appears on the spark plugs. Secondly, there may be quality issues with the spark plugs themselves, where the oil enters through the threads, necessitating replacement with new spark plugs. A spark plug is a component in the ignition system of a gasoline engine that introduces high-voltage current into the cylinder to generate an electric spark, igniting the combustible gas mixture. The spark plug mainly consists of a terminal nut, insulator, terminal stud, center electrode, side electrode, and shell, with the side electrode welded onto the shell.
Speaking of oil on spark plugs, I encountered this issue last week when I was fixing my car. As soon as I opened the engine cover, I found the spark plugs covered in grease and smelling a bit like engine oil. After consulting a professional friend, I learned that this is mostly due to worn piston rings or faulty valve guide seals, which allow oil to seep into the combustion chamber through the gaps and eventually coat the spark plugs. Over time, this can make the car hard to start, cause engine shaking, and may even lead to a significant increase in fuel consumption. If left unchecked, it could damage other components. Upon inspection, I found that my car hadn’t had its piston rings replaced after tens of thousands of miles, which was the root cause. I suggest you address this promptly and not let it escalate like I did. Now that I’ve replaced the parts with new ones, the engine’s performance has improved noticeably. Also, remember to maintain the engine regularly, including checking oil seals and changing the engine oil. Preventive maintenance is much more hassle-free and cost-effective than repairs, especially for older cars—so take good care of them.
