i am getting my car ready for another winter. i have a 2002 pontiac grand prix, 3.8 litre V6. during the summer i use 10W30. i am going to give amsoil a try. should i stick with the 10W30 or switch to the 5W30 during the winter.
With Amsoil, and the fact that your manual says 10w-30 is good to 0 degrees F, I would stay with 10w-30 ATM. Well, unless it routinley gets below 0 in your neck of the woods, in which 5w-30 would be better. But it does say 10w-30 is preferred in the 3800 series 2 manual