Positive Crankcase Ventilation System
WARNING: This page is about a different car, the 2019 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.
The crankcase ventilation system is used to consume crankcase vapors in the combustion process instead of venting vapors to the atmosphere. The system consists of one circuit, a primary part load circuit. In this circuit the gases and oil vapors from the crankcase are returned via an internal ventilation into the cylinder head cover that has an internal oil separator (2). The separated oil from the blow-by gases flows back to the camshaft area through the oil drain valve (3).