1. PCV valve: The PCV (positive crankcase ventilation) valve is responsible for regulating the flow of crankcase gases back into the engine. A faulty PCV valve can cause excessive pressure in the crankcase, which can force oil vapors into the air intake system.
2. Piston rings: Worn or damaged piston rings can allow oil to leak into the combustion chamber, where it can be burned and turned into oil vapors. These vapors can then be drawn into the air intake system through the PCV valve.
3. Oil fill cap: A loose or missing oil fill cap can also allow oil vapors to escape into the air intake system.
4. Turbocharger: If your F250 has a turbocharger, a faulty turbocharger seal or bearing can also cause oil to leak into the air intake system.
5. Overfilling: if the oil level in the engine is too high, it can overflow and enter the air filter box
To determine the exact cause of the oil in the air filter intake box, you may need to have the vehicle inspected by a qualified mechanic.
