I own a 99 Olds Intrigue with the 3.5l engine. I have read lately on how the oil life monitor works and I am about convinced to switch from Mobil 1 back to dino and using the oil life monitor as far as changes go. After I bought the car two years ago I put Mobil 1 in. It was spring in Houston. The oil life monitor allowed me approx. 7000 miles. At the next oil change I put dino in, same grade. Again I got 7000 miles per the monitor. I have since been running Mobil 1. I read a pretty convincing arguement that dino oils are lasting longer than originally thought. It has just about convinced me and I have been running syn for 15 years now. Is anyone out there using their oil life monitor with dino oils? I do not drive either of my vehicles that hard, and I could sure save some money as I change the oil myself. I know the prevalent opinion on this board is syn for extended drain intervals, but could GM possibly be right? http://www.gm.com/company/gmability/environment/gm_and_the_env/releases/oillife_monitor_041603.html