2007 Chevy Suburban Oil Loss

Engine Mechanical problem
2007 Chevy Suburban V8 Four Wheel Drive 55,000 miles

How much oil should a suburban burn between oil changes every 3 to 4 months?

I had some warranty work done to replace what the service manager at the dealer called a baffle under the valve cover. Oil was getting lost and there was no sign of oil leaks anywhere on the car. Te check engine light has now come on and the engine was low on oil again when I had it changed yesterday. I have had to add oil between oil changes ever since the warranty work was done. Any thoughts or advice is appreciated.

Pat