Crankcase Ventilation System Description: Operation
WARNING: This page is about a different car, the 2004 Suzuki Swift + and 2004 Chevrolet Aveo. However, it is still accessible from the selected car via links, so may be relevant.
The primary control of engine crankcase blow-by gas is the oil separator. The oil separator separates the oil from the blow-by gases and meters the flow of blow-by gas according to the manifold vacuum signal. The manifold vacuum draws the blow-by gases from the oil separator into the valve cover then into the intake where it is consumed by the normal combustion process. The volume of blow-by gas entering the intake manifold is precisely controlled in order to maintain idle quality.