The valve consists of two chambers separated by a piston and a spring. The crankcase pressure is drawn from the crankcase via the engine vacuum that is generated in the air intake and created by ...

The positive crankcase ventilation valve releases exhaust gas and unburned fuel from the engine block into the intake ... air pressure, the PCV valve maintains the optimal level of vacuum in ...

A car can backfire when fuel vapors ignite in the exhaust system or intake ... (EGR) valve or an engine vacuum leak can cause ...