As far as I am concerned it directly relates to a lot of miles driven out on what is really a factory recommended light weight oil. 5W20 is not an oil I would use unless I never saw the high side of zero degrees.
If you have any miles on yours at all, change up to something like a 10Wxx in the winter and something like a 10 or 20W40 for the summer use. And engine life will be prolonged.
What derf said is right, but high mileage added to it aggrevates the situation.
Me, I live in the SW where a third of the year it is triple digits.
I run 20W50 year around or 15W50 Mobil 1 depending on my car. I do not use any oil at all. At the moment, January 5, 2012 at 10PM it is 55 degrees. I have lived places where that was a high temperature in July.

Well, it's cold here in Massachusetts (most nights around 10 degrees), so I'm thinking 10W30. Probably going with Quaker State oil, which is my preferred oil for non-high performance vehicles, and a cheap oil filter. If it was for a high performance vehicle I usually go with Mobil 1 oil and a Purolater PureONE filter, but I see no need for the high end stuff in my DD.

Hi. Welcome, I Love Saturns. I have owned a 99 Saturn since 2006, super fun cars. My sattie uses a quart of oil towards the end of oil change, and i use Mobil 1 10/30, and also a K&N oil filter every 3,000 miles. Enjoy your Sattie.

Welcome. love the Sattie's.