SEPARATOR.
Part Number: 06H103495E
Supersession(s): 06H-103-495-E; 06H103495A; 06H103495AC; 6H103495E

This part is compatible with a wide range of Volkswagen Auto Group (VAG) vehicles, primarily those equipped with 1.8T or 2.0T engines from model years 2008 to 2017. 
Audi: A3, A4, A5, Q5, TT (Quattro and FWD models)
Volkswagen: Beetle, CC, Eos, Golf, GTI, Jetta, Passat, Tiguan
Other VAG brands: SEAT and Skoda models also use this part

Function and common symptoms of failure
The PCV oil separator separates oil vapors from the crankcase gases, returning the liquid oil to the oil pan and routing the clean gases into the intake manifold to be burned off. A malfunctioning PCV valve can cause various engine problems: 
Engine performance issues: Symptoms include rough idling, misfires, or a check engine light.
Increased oil consumption: A bad separator may fail to separate oil effectively, leading to excessive oil burning and blue smoke from the exhaust.
Sludge or condensation buildup: Improper ventilation can cause gunk to form under the oil cap or in engine components.
Oil leaks: The added pressure from a clogged system can force oil past seals and gaskets, leading to leaks.