Causes:
* Valve Cover Gasket Failure: This is the most common culprit. The valve cover gasket seals the top of the engine, preventing oil from leaking out. If it's worn, cracked, or damaged, oil can seep into the spark plug tubes.
* Head Gasket Failure (Less Likely, but More Serious): A blown head gasket allows coolant or oil to mix, and in some cases, oil can find its way into the spark plug tubes. This is a much more extensive and costly repair.
* PCV Valve Problems: A faulty Positive Crankcase Ventilation (PCV) valve can cause excessive crankcase pressure, forcing oil past seals and potentially into the spark plug tubes. This is less likely to directly fill the tubes but can contribute to the problem.
* Worn Valve Stem Seals: These seals prevent oil from leaking down the valve stems. If they're worn, oil can accumulate in the combustion chamber and then drain into the spark plug tubes. This is usually indicated by more significant oil consumption.
What to Do:
1. Don't Start the Car: Running the engine with oil in the spark plug tubes can lead to misfires, damage to the catalytic converter, and further engine damage.
2. Inspect the Valve Cover Gasket: Carefully examine the valve cover gasket for any visible signs of damage, cracks, or leaks.
3. Check the Oil Level: Check your oil level to assess the extent of the oil leak. Low oil is a clear sign of a problem.
4. Professional Diagnosis: This is not a DIY repair unless you have significant mechanical experience. Take your Neon to a qualified mechanic for a proper diagnosis. They'll be able to determine the exact cause of the oil leak and recommend the necessary repairs.
5. Avoid Further Driving: Driving with oil in the spark plug tubes risks significant engine damage.
Potential Costs:
Replacing a valve cover gasket is relatively inexpensive compared to a head gasket repair. Head gasket replacement is a much more involved and costly repair. The PCV valve is the least expensive to replace.
In short, oil in the spark plug tubes is a warning sign of a more significant problem. Getting it diagnosed and repaired promptly is crucial to prevent more extensive and costly damage to your engine.
