Your Sunfire does not have that many miles on it. Keep the oil changed about every 5000. The manual probably calls for 5W-30 or 10W-30. I'd use the 10W unless I lived in Alaska. If a car gets older with many (150000+) miles on it, AND starts to burn some oil, then go to a heavier weight, say 20W-40 or 20W-50. As a last resort, and in warm areas, go to straight 30W. Cars' engines will last a very long time, if serviced regularly. If you've got an automatic transmission, that usually the first thing to worry about...at least on the expensive list. Change that fluid every year or 30K miles. The Sunfire will probably make it to 250K.