Check Valve. Crankcase Ventilation.
PCV Valve.

CHECK VALVE

Fits V60 Cross Country (2015 - 2016)

5CYL. B5254T12. 5CYL.
PCV Valve
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 Volvo V60 Cross Country won't stay in the dipstick tube, or that your oil cap hisses as the engine is running.