If you have an ecotec its more than likely going to be a front engine seal(really easy to do) or a rear engine seal(more difficult, gotta pull of trans.
Did he give you anymore details or just say "crankcase oil leak" thats a pretty broad statement.
How low on the stick are you before changes. Most all 4 cylinder engines will burn oil during operation and the oil does break down over time.
Do you notice oil leaking under your car?
If you've got at least 4.5->5 quarts just before you get your next oil change I really don't believe its anything to worry about.