* Failed PCV Valve: This is the most common cause. The PCV valve regulates crankcase pressure. A faulty valve can either be stuck open (allowing excessive oil to be drawn into the intake) or stuck closed (building up pressure in the crankcase).
* Worn or Damaged PCV Hose(s): The hoses connecting the PCV valve to the intake manifold and crankcase can crack, become porous, or detach. This allows oil to escape and be drawn into the intake. Look for cracks, kinks, or loose connections.
* Bad Valve Cover Gasket: A leaking valve cover gasket allows oil to seep out of the valve cover and into the PCV system, eventually entering the intake.
* Excessive Crankcase Pressure: This could be caused by a number of issues, including:
* Ring Problems: Worn piston rings allow combustion blow-by into the crankcase, increasing pressure. This is a more serious issue.
* Blocked Crankcase Ventilation System: Something might be obstructing airflow within the PCV system.
* Oil Separator Failure (if equipped): Some engines have an oil separator to help prevent oil from entering the intake. If this fails, excessive oil can be drawn into the intake.
* Improper Oil Level: Overfilling the engine with oil can increase pressure and lead to oil entering the intake.
Troubleshooting Steps:
1. Check the PCV valve: Inspect it for proper movement. It should move freely when you try to push it in and out. Replacement is inexpensive and often solves the problem.
2. Inspect all PCV hoses: Look carefully for cracks, holes, or loose connections. Replace any damaged hoses.
3. Check the valve cover gasket: Look for oil leaks around the valve cover. A leaky gasket needs to be replaced.
4. Check the oil level: Ensure it's within the recommended range.
5. Consider more advanced diagnostics: If the above steps don't solve the problem, you may need professional help to diagnose more serious issues like worn piston rings or a blocked crankcase ventilation system. This might involve a compression test or a thorough inspection by a mechanic.
Ignoring oil in the air intake can lead to further engine damage, as oil can contaminate the air/fuel mixture, fouling spark plugs and potentially causing misfires or even engine damage. Addressing this issue promptly is important.
