The Saturn S Series is fairly well known for going through oil. From what I have learned, it is due to a design flaw in the piston rings, and how they eventually become gummed up with carbon and stick in their grooves, thereby not sealing the combustion chamber properly and allowing oil to seep past the pistons to be burned as the engine is running.

This is annoying, most definitely, but so long as one keeps an eye on there oil level everything should be fine. I've read that a quart of oil per 1000 miles is about average for an oil-burning Saturn...mine burns it a little quicker, about every 500-700 miles. Running synthetic slows the process some in my experience, but doesn't stop it. If one wanted to permanently resolve this, I believe they would have to remove the pistons from the motor and thoroughly clean them, making sure all the carbon was removed from the rings and the grooves. Otherwise, I advise just making sure you have oil on hand at all times, and check your level every time you fill up and top it off when it gets as much as a half quart low.

I wanted to add this complaint so anyone who might be considering purchasing one of these cars would know what to expect in this respect.