What Causes Oil Leakage at the Spark Plug Position?
2 Answers
The reasons for oil leakage at the spark plug position are as follows: 1. Damaged fuel injector; 2. Loose valve cover gasket seal; 3. Issues with piston rings and valve oil seals. Below is an introduction to spark plugs: 1. Standard spark plugs: The insulator skirt is slightly recessed into the shell end face, with the side electrode outside the shell end face, making it the most widely used type. 2. Extended insulator spark plugs: The insulator skirt is longer and protrudes beyond the shell end face. It offers advantages such as high heat absorption and good anti-fouling capabilities, and it can be directly cooled by incoming air to lower temperature, thus reducing the likelihood of hot spots and providing a wide thermal range. 3. Fine electrode spark plugs: These have very thin electrodes, characterized by strong sparks and excellent ignition performance. They ensure quick and reliable engine starts even in extremely cold conditions, with a wide thermal range suitable for various applications.
I find that oil seepage around the spark plug area is quite a common issue, and it can be really frustrating when encountered during driving. Possible causes include aging seals leading to oil leakage, as the rubber gaskets around the spark plugs can become hard and brittle over time, especially in regions with significant temperature fluctuations. Another common factor is damage or improper installation of the valve cover gasket—assembly errors like loose screws can also cause gradual oil seepage. Long-term high-load operation of the engine can generate pressure that forces oil up through piston ring gaps, resulting in oil seepage. Once, while replacing the air filter myself, I accidentally bumped the spark plug cover and discovered this issue, which later caused a slight delay in engine startup. A professional mechanic fixed it by replacing the gasket for a little over a hundred bucks. I recommend getting it checked at a reputable repair shop as soon as possible—don’t wait until severe oil seepage affects the ignition coil, causing hard starts or even smoke and fire hazards. Regularly inspecting seal conditions during maintenance can effectively prevent this problem.
