Grand Cherokee 2WD L6-4.0L VIN S (1997)
Crankcase Ventilation (CCV) System: Description and Operation
CRANKCASE VENTILATION (CCV) SYSTEM
All engines are equipped with a Crankcase Ventilation (CCV) system. The CCV system performs the same function as a conventional PCV
system, but does not use a vacuum controlled valve.
Fig. 10 CCV System - 4.0
A molded vacuum tube connects a fitting on the intake manifold to a fixed orifice fitting of a calibrated size. This fitting meters the amount of
crankcase vapors drawn out of the engine. The fixed orifice fitting is located on the top/rear of cylinder head (valve) cover (Fig. 10).
A fresh air supply hose is connected between a fitting on the air cleaner housing and the air inlet fitting at the top/front of cylinder head cover (Fig.
10).
When the engine is operating, fresh air enters the engine and mixes with crankcase vapors. Engine vacuum draws the vapor/air mixture through the
fixed orifice and into the intake manifold. The vapors are then consumed during engine combustion.
