Positive Crankcase Ventilation

The PCV Valve is an important part of a car's emissions control system. The PCV valve takes unburned gases that have escaped the combustion chambers by slipping past the pistons into the crankcase and sends them back into the intake manifold, where they ultimately rejoin the air-fuel mixture and are reburned. The PCV valve essentially recycles these escaped gases, reducing air pollution and preventing moisture buildup inside the engine.