Positive Crankcase Ventilation: Description and Operation

The crankcase emission controls prevent crankcase gases from being released into the atmosphere. Instead, the gases are routed to the intake manifold. Crankcase gases are removed from the crankcase by positive crankcase ventilation (PCV). Intake manifold vacuum draws the crankcase gases out of the crank housing into the intake air stream, where they get ignited in the combustion process.

Fig. 44 Positive Crankcase Ventilation:

There are four vapor hoses (PCV hoses) to complete the PCV system, Fig. 44. The routing is as follows:
PCV hose #1 : From passenger side valve cover to oil filler neck
PCV hose #2 : From passenger side valve cover to throttle valve housing (intake connection is before throttle valve)
PCV hose #3 : From oil filler neck to throttle valve housing (intake connection is before throttle valve)
PCV hose #4 : From oil filler neck to throttle valve housing (intake connection is after throttle valve)

The vacuum in the throttle housing draws the oil fumes through the four PCV hoses into the intake system.