I'm doing an oil change for a buddy of mine so he can send a sample into Blackstone for a UOA. My question is does it matter if the car isn't warm when I change it? As in the car has been sitting for a couple days, I just show up and change it without starting the car. He owns a Trans Am that doesn't go out in the rain and that's what they are calling for all this week. Just want to make sure if I did it this way that the sample wouldn't be "contaminated" in any way.