CRANKCASE EMISSION CONTROL SYSTEM Description This system returns blow-by gas to both the intake manifold and carburetor air cleaner. The positive crankcase ventilation (P.C.V.) valve is provided to conduct crankcase blow-by gas to the intake manifold. During partial throttle operation of the engine, the intake manifold sucks the blow-by gas through the Rev. valve. Normally, the capacity of the valve is sufficient to handle any blow-by and a small amount of ventilating air. The ventilating air is then drawn from the air cleaner, through the hose connecting air cleaner to rocker cover, into the crankcase. Under full-throttle condition, the manifold vacuum is insufficient to draw the blow-by flow through the valve, and its flow goes through the hose con- nection in the reverse direction. On vehicles with an excessively high blow-by some of the flow will go through the hose connection to the carburetor air cleaner under all conditions. :1) Fresh :lr Ventllation hose Filter *Elovwbv gas l c Sealed filler can Bafn plot: 6 01 level >- g_ - - _ . i t gauge 0 J a o l W T P c.v valve ._ Seal mm!L secsasA inspection P.C.V, VALVE AND FILTER With engine idling, remove the ventilator hose from P.C.V, valvet If the valve is working, a hissing noise will be heard as air passes through the valve and a strong vacuum should be felt immediately when a finger is placed over valve inlet. m5 secwsu VENTlLATlON HOSE 1. Check hoses and hose connections for leaks. 2. Disconnect all hoses and clean with compressed air. 4' If any hose cannot be freed of obstructions, replace.