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 ...

Some emissions control systems also rely on this negative pressure to prevent crankcase fumes from escaping ... When the car is turned off, the system captures fuel vapor in a charcoal canister ...

Blow-by-liquid from the positive crankcase ventilation system may collect on the intake air hose of impacted models. Not only is BMW facing the headache of recalling over 720,000 vehicles in the ...