The positive crankcase ventilation valve releases exhaust gas and unburned fuel from the engine block into the intake manifold. All engines allow some exhaust gases, unburned fuel and oil to ...

One of the most common components in an engine’s emissions control system is the positive crankcase ventilation valve, or PCV valve. Its job is to allow the air and fuel vapor that gets past ...

is a damaged positive crankcase ventilation (PCV) system. During standard operation, it's normal for small amounts of fuel or blow by to slip into the crankcase. The PCV system is designed to vent ...