I've got a 2010 Mazda 3 S with the 2.5L engine. I don't know whether the previous owner ever changed the PCV valve and I'd like to check it but not sure where it is on this car. Can somebody give me specifics about where to look?

 

Hidden behind/ underneath the intake manifold.
Its not normal to need replacement.

 

There's a mechanic in Houston, TX USA who has a YouTube channel where he gives advice about cars. He says that a clogged or bad PCV valve can cause a car to burn excess oil, and says that since the valve is so inexpensive he recommends changing it out every 3 - 4 years. I did change it on a 2005 Lincoln Town Car after I bought that used, and wanted to do the same on my Mazda as a precaution. From what you've said, though, it doesn't seem like it would be easy to get at on my Mazda 3.

 

Not easy. Intake manifold requires removal.