* PCV System Failure: The PCV system is designed to vent crankcase pressure and blow-by gases. These gases contain oil vapor. If the PCV valve is clogged, cracked, or the associated hoses are damaged or disconnected, crankcase pressure builds up. This pressure can force oil vapor (and even some liquid oil) past seals and gaskets, ultimately finding its way into the intake manifold, which is connected to the throttle body.
* Valve Cover Gasket Leak: A leaking valve cover gasket can allow oil to escape, and with increased crankcase pressure (due to a failing PCV system), this oil can be pushed towards the intake.
* Other Leaks/Cracks: While less likely to directly cause oil in the throttle body, cracks in the intake manifold or other seals near the valve cover could contribute to the issue, especially in conjunction with a failing PCV system.
In short, the root cause is almost certainly a malfunctioning PCV system, creating excessive crankcase pressure that pushes oil into the intake. Ignoring this can lead to serious engine damage, including:
* Fouled Spark Plugs: Oil in the combustion chamber will foul spark plugs, leading to misfires and rough running.
* Damaged Catalytic Converter: Oil in the exhaust stream can damage the catalytic converter.
* Engine Sludge: Excessive oil buildup in the crankcase can lead to sludge formation, reducing engine lubrication and lifespan.
What to do:
1. Check the PCV valve: This is the cheapest and easiest thing to check first. It's relatively easy to access and replace. A clogged valve will often show signs of oil buildup.
2. Inspect all PCV hoses: Look for cracks, kinks, or disconnections. Replace any damaged hoses.
3. Check the valve cover gasket: Look for signs of leakage. A leaking gasket might need replacement.
4. Inspect the intake manifold and associated seals: Look for cracks or leaks.
If you're not comfortable performing these checks yourself, take your Saturn Ion to a qualified mechanic for diagnosis and repair. Delaying addressing this issue could lead to significant engine damage and expensive repairs down the road.
