The valve cover gasket is a seal between the valve cover and the cylinder head. It prevents oil from leaking from the valve train into the spark plug tubes. Over time, the valve cover gasket can become worn or damaged, allowing oil to leak into the spark plug tubes.
2. Clogged or restricted PCV (positive crankcase ventilation) valve
The PCV valve is a small valve that helps to regulate the pressure in the crankcase. A clogged or restricted PCV valve can cause pressure to build up in the crankcase, which can force oil past the valve cover gasket and into the spark plug tubes.
3. Faulty oil control rings
The oil control rings are rings on the pistons that help to control the amount of oil that is used to lubricate the piston. If the oil control rings are worn or damaged, they can allow oil to leak into the combustion chamber, where it can be burned and turned into carbon deposits. These carbon deposits can build up on the spark plugs and prevent them from firing properly, leading to a misfire.
4. Damaged or cracked spark plug tube seals
The spark plug tube seals are small rubber seals that fit around the spark plugs. They prevent oil from leaking from the spark plug tubes into the combustion chamber. Over time, the spark plug tube seals can become damaged or cracked, allowing oil to leak into the spark plug tubes.
