I've notice lately that my wife's 2012 cx9 seems to be using oil. Around 4,000 miles post oil change, the oil level is around a quart above the fill line. Has anyone had any issues with this engine using oil? This was a new cx9 and has been taken care of since we got it. I typically change the oil every 5k, but am wondering if I need to start sooner...

 

That doesn't sound low to me, 5k is fine !

 

All engines use oil. The cylinder walls have a coating of oil at all times so they have to use some. Most manufacturers consider 1 qt every 800 miles acceptable,but that is the spec they use when they have a tech do an oil consumption test before a warranty engine repair. An occasional decarbon of the engine will extend ring life. I use Techron once before each oil change.

 

Change the PCV valve, Mazda doesn't! Hixx you need to start changing these!
A faulty PCV valve will make the engine use more oil. So when the consumption seems to go up, change it.

 

LOL, been doing this since 1976 for a living. Just clean your PCV valve if it's factory. The Chinese PCV valves that you replace it with is what will cause oil consumption.