240 L4-2.3L SOHC VIN 88 B230F (1986)
Positive Crankcase Ventilation: Description and Operation
Between the crankcase and the intake manifold there is a hose which is connected to a nipple on the intake manifold. Between the valve cover and the
air cleaner there is a hose connected for fresh air supply.
The partial vacuum that exists in the intake manifold during engine operation, creates a vacuum in the crankcase through the hose. Fresh air is supplied
to the valve cover by the air cleaner and hose. A plate in the valve cover ensures that the fresh air circulates sufficiently in order to mix with the
crankcase gases.
As fresh air passes through the air cleaner, impurities are prevented from entering the engine. During high or medium amounts of vacuum in the
crankcase, which occurs during idling and when under light loads, the system operates as described above. When vacuum in the crankcase is less then
that in the air cleaner, which occurs at full load and/or with large air-flow quantities, no fresh air is supplied. Instead, the flow in the connection
between the valve cover and the air cleaner reverses and the crankcase gases pass both ways. In this way, the PCV system can deal with relatively large
quantities of crankcase gases without any entering the atmosphere.
COMPONENTS:
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Oil Trap And Flame Guard System
FLAME GUARD
Prevents a possible backfire from entering the crankcase. Should the backfire enter the crankcase, it could ignite the blow-by gases. Periodic cleaning or
replacement (see "MAINTENANCE PROCEDURES") of the flame guard helps prevent crankcase over-pressure. Fig. 8.
Fig. 9 P.C.V. NIPPLE
NIPPLE
Regulates the crankcase gas flow and limits the maximum crankcase vacuum. Fig. 9.