Valve Assembly - PCV.
External. PCV Valve.

PCV Valve

ATS; 2.0L; Fresh Air (Front). ATS; 2.0L; Front. Camaro; 2.0L; Fresh Air. CT6; 2.0L; Fresh Air. CT6; 2.0L; Turbo Vacuum. CTS; 2.0L; Front. Envision; 2.0L; Fresh Air Valve. Equinox, Terrain; 2.0L; Fresh Air. Malibu; 2.0L; Primary. Regal Sportback; 2.0L; Front (Fresh). Regal TourX; Front (Fresh). Traverse; 2.0L; Fresh Air.
PCV Valve - Repair or Replace
If your PCV system is malfunctioning, you may notice any of several symptoms: if your tailpipe smokes or your engine idle speed is high or erratic, the PCV valve or its associated parts may need service. You may also notice that the dipstick in your 2015 Cadillac ATS won't stay in the dipstick tube, or that your oil cap hisses as the engine is running.