I am not sure if these is typical on 2001 Pathfinders models but whenever its hot out and when i turn the AC on also on a hot day the fan runs very loud. it sounds like a Mac truck!!! I understand running the AC will rob the vehicle of some power but i have to kind of floor the peddle to move the truck. The belt have been changed and a tune-up done recently but i get the same results. This is normal or do i need to be concern?