Originally posted by dark_rex

why would you want to warm the oil? have you ever seen warm oil drain out of a car? it's so liquid is splashes EVERYWHERE.

plus, why would you want any of the oil in the block? a cold engine will have all the dirty oil in the pan, ready to drain. you're leaving some of the oil in the car when you do it on a warm engine.

dR
I've heard that all fluids should be changed when warm, I always figured it had something to do with it being circulated so that sediments would be stired up and come out with the oil. If the oil is cooled sediments settle out on flat surfaces inside the engine, leaving them inside when it is drained. I've always changed my oil warm, and yea, it is quite liquid, but that just means it drains quickly . Just gotta be careful and not try chaning when it's too hot, or you'll have scorching oil poured all over your hand when you remove the drain plug (done it more than once)