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Excessive Oil Consumption & Check Engine Light on 2016 A6 3.0T

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Chris P. · rep 0 · May 26, 3:45 AM · 1 replies · solved · Question

Vehicle: 2016 Audi A6 3.0T Premium

My 2016 Audi A6 3.0T Premium has recently started consuming an alarming amount of oil. I'm having to add a quart every 1,000-1,500 miles, which seems way too high. On top of that, the check engine light (CEL) came on last week, and I also noticed a bit of white smoke from the exhaust on cold starts.

I've read online that excessive oil consumption can be a common issue with the 3.0T engine, sometimes related to the PCV valve. Could this be the culprit? Are there any specific codes I should look for if I get it scanned? The car has about 85,000 miles on it.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 26, 3:45 AM

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ClearTheCode admin answer:

Excessive oil consumption and a check engine light on a 2016 Audi A6 3.0T with the supercharged V6 engine (CREC or similar) are indeed often linked to a failing PCV (Positive Crankcase Ventilation) valve, or more accurately, the oil separator assembly. This is a well-documented issue for this engine family.

Common Causes:

  • Failing PCV/Oil Separator: The diaphragm inside the PCV valve can tear, leading to excessive vacuum in the crankcase. This pulls oil vapor directly into the intake manifold, where it's burned, causing high oil consumption and potentially white smoke.
  • Vacuum Leaks: A failing PCV can also create vacuum leaks, affecting engine idle and performance.
  • Clogged Breather Hoses: Less common, but blockages in the PCV system can also lead to pressure issues.

Troubleshooting & Diagnostics:

  1. Check for DTCs: If your CEL is on, get the car scanned. Common codes associated with PCV issues or related vacuum leaks include:
    • P0456: Evaporative Emission System Leak Detected (Very Small Leak)
    • P0507: Idle Air Control System RPM Higher Than Expected
    • P0171/P0174: System Too Lean (Bank 1/2) – indicating unmetered air entering the engine.
  2. Vacuum Test: A simple test involves trying to remove the oil filler cap while the engine is running. If it's very difficult to remove or there's a strong sucking sound, it's a strong indicator of a failed PCV valve creating excessive crankcase vacuum.
  3. Visual Inspection: Look for oil residue around the PCV assembly or vacuum lines.

When to See a Shop: Given the check engine light and significant oil consumption, it's crucial to have your A6 inspected by an Audi specialist. A failing PCV valve can lead to other issues, including premature wear on engine components due to oil dilution or carbon buildup. The replacement of the PCV valve on the 3.0T engine is a moderately complex job, often requiring removal of the supercharger, and should be performed by experienced technicians. They can confirm the diagnosis, replace the faulty part, and clear any stored fault codes.

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