I ordered one from Advanced Autoparts and found pages on how to replace it, but none of them said what it controls. Only reasons I'm replacing it is because I have a 95 and its seems to be in an easy position, its probably never been replaced before (135K miles), and it was only $3.50.

 

PCV stands for Positive Cranckcase Ventilator. From what I remember pressure builds up in the crank and these gas's and carbon build ups need to be released. In which the PCV valve comes into play. You see that the PCV valve is in the top of the intake manifold. This puts these small amounts of gas's into the combustion chamber to dispose them in a safer manner. Instead of releasing them into the atmoshpere which is bad for the enviorment. Someone may correct me... but thats what I remember

 

thanks, so by putting those small amounts of gases into the combustion chamber, its it hurting performance in any way? i'm still going to replace it either way though.

 

There's nothing you can really do about it. The way you can test it is take out the PCV valve and shake it. If it rattles it is generally good... but the carbon clogs it up and thats when you need to replace it.

 

Where did you find pages on how to replace it?

 

this page had a nice picture of it, i went out and looked at mine and it just looks like it comes out like a screw.

 

http://forums.maxima.org/showpost.ph...4&postcount=38

 

just pull on it...it pops right out...10 minute job.