Positive Crankcase Ventilation
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Positive Crankcase Ventilation (PCV) system prevents crankcase vapors from escaping into the atmosphere. Crankcase vapors are routed from crankcase through a vacuum-controlled PCV valve, then delivered back into the cylinders. PCV system provides primary control of crankcase blow-by vapors, according to manifold vacuum. When manifold vacuum is high (at idle), PCV restricts vapor flow to maintain a smooth idle condition.