Positive Crankcase Ventilation: Description and Operation

The engine is ventilated through a part-load and a full-load breather; one on each camshaft cover. These flexible plastic hoses incorporate O-ring seals and quick release connectors.
The part-load breather ventilates the left-hand camshaft cover (Bank 2) and feeds onto the throttle body adaptor and the purge valve. This breather is connected between the oil separator in the cover and the induction elbow.
The full-load breather ventilates the right-hand cover (Bank 1) and is connected between the oil separator in the cover and the air intake duct between the mass air flow sensor (MAFS) and the throttle body.
The MAFS unit combines the two sensors: one for air flow and one for air intake temperature. It is a hot wire sensor that provides an input which is (approximately) proportional to the mass air flow into the engine.
Each camshaft cover oil separator consists of wire gauze packed into an open ended enclosure in the top of the cover, below the breather outlet.