Vehicle in question is a 2002 Grand Am GT with GM's 3.4L V6. I live in Toronto, Canada to give you an idea of the climate and the car is NOT driven hard. The car has about 30,000 miles on it with a current OCI of around 3k miles with whatever oil the shop uses. The last oil change (last week) was with Valvoline in either 5W30 or 10W30 (I'm not sure cause the work order says 5W30, but I just noticed today that the window sticker they put on says 10W30 - no big deal since it will be taken out this fall at the latest). Anyway my question is do you guys think this oil can hold up for 4000-5000 miles with 90% of them being highway miles of trips over 20 miles. This will get me to fall when I will start my new oil stategy: I plan on chaning over to M1 in the fall (will start doing my own oil changes) with two changes a year (0W30 or 5W30 in the fall and 5W30 in the spring). I figure I will put about 8,000 miles on the oil with that OCI. I will also start using a larger oil filter (I think it will be the equivlent to AC Delco's xxx-52 instead of the tiny filter speced for this car) and am considering changing the filter and topping up oil around 4,000 miles in the summer, but I'm not sure if I'll do this in the winter. Any opinions are appreciated.