Here's why this is serious and what you should do:
* Head Gasket Failure: This is the most common culprit. The head gasket seals the combustion chamber from the engine's cooling system and oil passages. A blown head gasket allows oil to mix with coolant (you might see milky oil or a loss of coolant), and in this case, it's forcing oil into the cylinder.
* Cracked Cylinder Head: A crack in the cylinder head can also cause oil to leak into the combustion chamber. This is a more significant repair than a head gasket replacement.
* Valve Cover Gasket Leak (Less Likely): While less likely to directly end up *in* the spark plug well, a severely leaking valve cover gasket *could* contribute to oil getting near the spark plug area, but it wouldn't usually be forced into the well with that much pressure.
What you should NOT do:
* Don't try to start the car. Continuing to run the engine with this problem will likely cause significant further damage.
What you SHOULD do:
1. Stop driving the car immediately.
2. Have a mechanic diagnose the problem. They'll need to perform a compression test and possibly a leak-down test to pinpoint the exact cause. A visual inspection might reveal external signs of leakage.
3. Get a repair estimate. Repairing a blown head gasket or a cracked cylinder head can be expensive, potentially reaching thousands of dollars depending on the labor costs in your area. Consider the age and overall condition of the vehicle before committing to a significant repair.
Ignoring this issue will lead to catastrophic engine damage. Get it checked out by a professional as soon as possible.
