If using that much oil it should have a good bit of Blue Smoke out the exhaust pipe ALL the time?
Sometimes you can make a guess about the issue by checking to see when the Blue smoke out the tail pipe actually occurs correlated to other factors.
1. If you get a cloud of Blue Smoke immediately upon start up AFTER the vehicle has set overnight then we can guess that the valve guides in the cylinder heads are worn allowing oil to seep through and down into the combustion chamber.
2. If you get Blue Smoke upon hard acceleration after the vehicle is at operating temperature then we can guess that we have a piston oil ring problem and or the engine needs a oil slinger diverter plate installed inside the oil pan.
3. Barely perceptible Blue Smoke at anytime we could guess that the PCV system is pulling oil mist from the valve cover into the intake because of a bad valve cover PCV baffle design.
Certainly not a complete list or exact science. How many miles are on this 2009 Yukon?
i just realized today that my recently acquired 2009 Tahoe with 197,000 miles is using oil at a rate of 1 quart per 1200 miles approx. I will be watching closely over the next few weeks to try to figure out when it is producing Blue Smoke. Hoping for the easy valve cover fix but I do not know what the past owner REALLY did on maintenance, I just have his word that he always ran synthetic and that it was changed regularly. Not sure if regularly means when the OLM said to change it or if he was a 3000 mile max. type guy.
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There is a service bulletin about excess oil usage in the 07-10 GM Trucks and one of the items is a different driver side valve cover. Seems like the original cover had the pvc intake close to where oil sprays when the AFM is working, so the PVC picks up alot of extra oil. Take the air hose off the front of the throttle body and see if the intake is full of oil. That will prove the PVC is causing most of the oil usage. I replaced my valve cover with the new recommended one and it fixed my issue. Any dealer can look up the issue and give you part numbers/info. Sorry I don't have them written down.

 

Thanks lt1gmc I bought a revised valve cover from Advance Auto Parts on Black Friday for 50 bucks. It is a quick and easy swap but once I got the old one off I realized it had already been changed and the old one was in fact the updated design. I went ahead and put the new one on anyway as my old valve cover had a lot of black oil buildup on the inside and I thought that maybe somehow that was contributing to a PCV system issue (doubt it) but for the price it was not too expensive of a test. I will just watch my oil level for the next few weeks and see what it does I guess. The black buildup inside the old valve cover probably indicates poor oil change intervals. I suspect the previous owner actually believed the OLM and run the engine for 10 to 15k miles between oil changes till the OLM told them it was time to change it over the last 197k miles. Oh well you win some and you lose some. I probably will not get the 400k that I wanted to out of this ICE I may have to settle for 300k or so. Hard Times ahead for ole dnt........................wish me luck man.

Dang it that is some black oil funk at nearly 200k. Normal?