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PCV Valve Replacement

Model: Audi A4 B7 - Years 2004-2008
Part: Valve

The PCV (Positive Crankcase Ventilation) valve serves to ventilate the crankcase; it is also known as a breather valve. There has been much discussion about the failure of this valve, to the extent that Audi has issued a Technical Service Bulletin acknowledging the manufacturing defect and has provided a warranty replacement with an updated version. Symptoms of malfunction typically include:
- Fluctuations in engine RPM with idle oscillations causing the engine to rev up to 2000-3000 RPM without pressing the accelerator. However, the engine control unit does not log any faults related to this anomaly. The replacement is extremely simple as it is mounted on the side of the valve cover: just disconnect the hoses and remove the mounting screws (a new gasket is also provided with the valve).

Updated on 11 February 2026 by ScegliAuto

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