t6dpilot

I have recently acquired a 2008 2.0TQ with 18k miles. I read that the PCV valve can go bad and the way to tell is to pull the oil filler cap while the car is running. If it runs rough and/or has suction, then the PCV is going bad. Is this true? I performed this test and I did experience both (suction of the cap and the engine ran a little rough and vibrated).

Thanks for the help!

A4Audi4Fun

Yes - my oil cap was stuck on tight when I had the PCV problem. Could also hear a hissing sound right after I shut the engine off and there was a DTC code (though no CEL). Replacement PCV, under warranty, removed all those symptoms.

Old Dog

When my PCV valve went I had a check engine light come on. When idling the car was a little rough, however once rolling it was pretty smooth, but lacked power. These were the symptoms for mine one week before trading it in for my 2011 Tiguan. It was covered under warranty.

91c2wrencher

FWIW, my $0.02 worth. The "pcv" valve you mention is not a term the Audi parts guy will recognize, try PRV, pressure regulator valve. I recently changed out mine as the engine had started to purge oil from the oil filler cap. very easy swap out. I didn't know it was a warranty item? ....2007 2.0TQ.....

ryan_qttro

Also called crankcase vent valve , if you can't open oil cap with engine running it's stuck open and gone bad

Old Dog

Just for the record, I double-checked my Audi work order to see what they called it. They referred to it as a PCV valve in the replacment write-up. It was replaced under the original warranty two weeks before the expiry date of 28 Dec 2010.

I do agree with you 91c2wrencher and ryan_qttro it is also called a pressure regulator valve or crankcase vent valve.

Milo65

When the pcv or prv valve fails you may see oil residue around the cap and or coils....You will probably throw a P01701 code (lean bank 1).