I can't believe that the 07 Suburban oil consumption problem hasn't been mentioned on this site, it is everywhere else. Many 07 Suburbans burn a lot of oil - GM will try to tell you that a quart every 1500 - 2000 is normal - which is just ridiculous. If you burn a quart every 1000 as mine did they will repair it (if you are under 100,000 miles). It's a big repair, major engine rebuild. In mine, there was a lot of valve train damage, so it's not just that the engine burns oil, it is slowly eating itself. It is a huge amount of work to get Gm to admit to this problem and fix it - I think they hoped I would just give up and let them off the hook.
Our Suburban starting burning oil at around 60,000 miles...several quarts between oil changes. The dealer required multiple oil consumption tests and offered several short term fixes up through our warranty at 106,000 miles, but did not want to rebuild the engine as it should have done (they said GM will only approve a complete rebuild after all other repair options have been exhausted). The dealer admitted to us that this condition is a known defect in the engine, GM is aware of it, and that they have a number of people with the same problem. We have a long history of these problems documented in our service record and are now again experiencing oil consumption problems starting at approximately 120,000 miles.
Due to our long service record of oil consumption problems, I hope that GM steps up to the plate and properly takes care of the repair at no cost to us, but we are prepared to fight them. My advice, if at all possible, is to get them to rebuild the engine while under warranty.