Signs of a bad PCV valve

[thexav]

What are the signs of a bad PCV valve?

A mechanic think my mums is on the way out in her car but I'm not so sure so just wondered what you guys thought the signs were of a bad PCV valve?

 

[wizzer]

This is the positive crankcase ventilation valve something I actually know a little bit about. It deals with blowby gases which contain unburned fuel & partially burned fuel (Hydrocarbons and Carbon monoxide) and sulfur, acids particulates and water all of which will degrade your oil and are nasty to spit out into the air. The PCV pulls these into the air intake where they can be safely burned in the engine.

If the engine crankcase builds up enough pressure then it can affect the engines performance, running lean etc. Water and oil can end up in odd places like the air filter eventually clogging the air filter. It can cause oil leaks, smoke, failures of gaskets and seals, misfiring engine, rough idling and increased oil consumption.

 

[herb]

What car is this?
On my last few cars I've had overfueling, limp mode from a leak within the pcv pipework. Nothing ever has been attributed to a specific valve. Although once a check valve had gone on my Leon but it isn't specifically known as a pcv valve

 

[TCJBOLDIE]

Are you referring to the one way valve that is on the rocker/valve cover that has a hose connected to the inlet manifold or plenum??