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Home >> BMW >> 1971 >> 3.0CSL Automatic Trans >> Repair and Diagnosis >> Engine Mechanical >> Auxiliary Emission Control Systems >> Crankcase Ventilation Systems >> Operation >> 220 Models
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220 Models

During normal engine operation, crankcase fumes and vapors are vented from cylinder head cover through flame arrestor and connecting hose to carburetor air cleaner. Fumes are then drawn through carburetor, into engine and burned. During periods of deceleration or engine idle, throttle valves are closed and there is no vacuum in air cleaner. Under these conditions, crankcase fumes and vapors are drawn directly into intake manifold through connecting hose located between intake manifold and cylinder head cover.