* Worn Turbocharger Seals: This is the most common cause. The seals within the turbo (shaft seals and possibly the oil return seal) wear down over time due to heat, age, and use. This allows engine oil to leak past the seals and into the turbo's compressor housing or exhaust housing, eventually being burned in the exhaust or dripping out. This is often accompanied by bluish-white smoke from the exhaust.
* Oil Return Line Restriction: The oil return line carries used oil back from the turbo to the engine. If this line becomes clogged with sludge, carbon deposits, or debris, it creates back pressure. This back pressure can force oil past the seals.
* Excessive Crankcase Pressure: High crankcase pressure, due to a failing PCV (Positive Crankcase Ventilation) system or other engine issues, can push oil into the turbocharger through the oil feed line.
* Failed or Weak Turbocharger Bearings: Worn bearings can allow the shaft to move excessively, damaging seals and leading to oil leaks. This is often accompanied by excessive turbo shaft play (you can often feel this if you manually move the shaft).
* Cracked or Damaged Turbocharger Housing: A crack in the turbo housing can allow oil to escape, although this is less common.
* Overfilling the Engine with Oil: This can increase crankcase pressure, contributing to oil leaks into the turbo.
* Faulty Oil Feed Line: A cracked or damaged oil feed line can allow oil to leak before it even reaches the turbo. This could also lead to insufficient oil supply to the turbo, resulting in bearing damage and subsequent oil leaks.
Diagnosing the problem:
To pinpoint the cause, a mechanic would likely:
* Inspect the turbocharger: This involves checking for shaft play, visual inspection for leaks, and potentially disassembly for a thorough seal inspection.
* Check the oil return line: This involves inspecting for clogs and ensuring proper flow.
* Check for excessive crankcase pressure: This might involve a crankcase pressure test.
* Inspect the PCV system: A malfunctioning PCV can lead to high crankcase pressure.
* Check the oil level: Verify it's not overfilled.
* Inspect the oil feed line: Check for leaks, cracks, or damage.
Ignoring a turbocharger drawing oil can lead to serious engine damage, including catastrophic turbo failure and potential engine seizure. It's crucial to address this issue promptly.
