- Faulty PCV valve: The PCV (positive crankcase ventilation) valve is responsible for regulating the flow of air and oil vapors from the crankcase to the intake manifold. If the PCV valve is faulty, it can cause excessive pressure to build up in the crankcase, which can force oil out of the hose and into the air filter.
- Clogged or damaged hose: The hose that connects the valve cover to the breather in the air filter can become clogged or damaged, which can restrict the flow of air and oil vapors. This can also cause excessive pressure to build up in the crankcase and force oil out of the hose.
- Worn piston rings: Worn piston rings can allow oil to leak into the combustion chamber, increasing the amount of oil in the crankcase. This can also cause excessive pressure to build up and force oil out of the hose.
Recommended solutions:
- Replace the PCV valve.
- Inspect and clean the hose that connects the valve cover to the breather in the air filter. If the hose is clogged, clean it with compressed air or a carburetor cleaner. If the hose is damaged, replace it.
- Have the cylinder head gasket checked for leaks. If the cylinder head gasket is leaking, it can allow oil and coolant to mix and overflow through the hose from the valve cover.
