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2017 Audi A4 B9 PCV Valve Replacement - Oil Consumption & Whistle

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Tom H. · rep 0 · May 22, 4:29 AM · 1 replies · solved · Question

Vehicle: 2017 Audi A4 2.0T Quattro Premium Plus

Hey everyone, I'm driving a 2017 Audi A4 2.0T Quattro Premium Plus, and I've been noticing a few concerning symptoms lately. First, my oil consumption seems to have increased significantly – I'm adding a quart every 1,500-2,000 miles. Second, I've started hearing a distinct whistling or whining sound coming from the engine bay, especially at idle or low RPMs. Sometimes the idle feels a bit rough too.

I did some research, and it sounds a lot like a failing PCV (Positive Crankcase Ventilation) valve. Is this a common issue on the B9 A4s with the 2.0T engine? What are the typical signs, and is it something a moderately skilled DIYer can tackle?

Also, could a bad PCV valve trigger any check engine lights or specific OBD codes? Any advice on diagnosing or replacing this would be greatly appreciated!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 4:29 AM

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ClearTheCode admin answer:

Your symptoms – increased oil consumption, a whistling/whining sound from the engine, and a rough idle – are classic indicators of a failing PCV (Positive Crankcase Ventilation) valve on your 2017 Audi A4 2.0T (EA888 Gen 3 engine). This is indeed a very common issue on these engines.

How a Failing PCV Valve Causes These Symptoms:

  1. Whistling/Whining: The PCV valve contains a diaphragm that can tear. When this happens, it creates a vacuum leak, causing the distinctive whistling sound as air is sucked into the crankcase.
  2. Increased Oil Consumption: A torn diaphragm or stuck valve can lead to excessive vacuum in the crankcase, which can pull oil vapor into the intake manifold, where it's burned off, leading to higher oil consumption.
  3. Rough Idle/Performance Issues: The vacuum leak created by a failing PCV can disrupt the air-fuel mixture, leading to a rough idle, misfires, and sometimes a loss of power.

Associated OBD Codes: A failing PCV valve, due to the vacuum leak, often triggers a Check Engine Light with codes related to lean conditions or idle control:

  • P0171: System Too Lean (Bank 1)
  • P0507: Idle Air Control System RPM Higher Than Expected
  • P0300, P0301-P0304: Random/Multiple Cylinder Misfire Detected (or specific cylinder misfires)

DIY Feasibility: Replacing the PCV valve on the EA888 Gen 3 engine is a moderately challenging DIY task. It's located on top of the engine, under the engine cover. You'll need basic hand tools, and it's crucial to use a genuine Audi or high-quality OEM replacement part. Be careful with the plastic hoses and connectors, as they can become brittle over time.

When to See a Shop: If you're uncomfortable working with engine components, or if the issue persists after replacement, it's best to take your A4 to an Audi specialist. They can perform a smoke test to confirm vacuum leaks and ensure proper installation. Ignoring a failing PCV can lead to long-term engine issues due to improper crankcase ventilation and excessive oil consumption.

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