Pressure regulating valve that bolts to front of head, also called the PCV valve.
If you are experience a loss of boost and also oil around the oil cap then theres a good chance your factory PCV valve is shot. Replace it with this updated VW/Audi part to get things running how they should be.
NOTE: When replacing with this version it is required that the breather hose must also be changed with part number 06F103215A
FITS: Mk5 Golf/Jetta 2.0T FSi, EOS 2.0T FSI, B6 Passat 2.0T, B7 Audi A4 2.0T
Ships in 1-3 days.