PCV systems are far more complex now, but they are also much better at controlling crankcase pressure.
Andrew Markel discusses a true shop story where a customer came in with an oil leak issue, only to find the PCV valve clogged.
Andrew Markel discusses the oil separator, and why you may not find this part right away when you look for it.
In this tip clip from the Quick Check Diagnostics class, instructor Jim Wilson talks about some simple test you can perform to verify proper functionality of the PCV valve. He goes on to discuss what to watch out for and how fuel trim can be effected.