The PCV valve uses the vacuum from the intake manifold to regulate the flow of gases from the crankcase.
Andrew Markel discusses a true shop story where a customer came in with an oil leak issue, only to find the PCV valve clogged. Sponsored by Auto Value and Bumper to Bumper.
The positive crankcase ventilation (PCV) valve is a little component that can cause big problems if it isn’t working. Neither your customer’s engine nor your job profitability will flourish if you don’t properly diagnose PCV leaks.