We know there are a lot of holdover ideas from days gone by that are no longer valid because certain things have changed. This seems like a stupid idea but it DOES seem to make sense. I like everyone have always changed my oil with a hot engine, waiting just long enough so that i don't burn myself. But back in the day when that idea was first born out of what seems obvious, oils were single grade. With today's multi grade it just hit me that draining oil cold with say 10w-40, the oil would be 4 times thinner ! Seems crazy to even consider a cold change, but why doesn't that make sense? What am i missing?