Im trying to explain to someone at work how oil works etc, so say you have a 5w40... I was saying it starts off at a thinner 5w and once up to operating temp is ends up at a 40w. Then he was saying well it thicker cold and thinner hot, so how does it do that and so on. I tried to explain VIIs etc... Can someone give me a website or something to print out to give to him. Id appreciate it! This is the only place I knew to ask for help lol.