[george kujanski]

Studda: in your previous post you say black is the absence of light...I say no, the absence of light (visible) is dark.

Black is a color which reflects very little of the visible spectrum of light to your eye.

If the underhood is sealed so no ambient light gets in, the engine does not turn black; it doesn't change color. The underhood becomes dark; i.e. there is no (visible) light. Now IF your eyes were sensitive to infra-red, in the above scenario you would "see" the infra-red coming from the warm engine, and the parts with higher emissivity would "look" hotter (or brighter).

George

[gearbanger]

George, that is correct as I learned in Physics. Therefore I do not believe this theory. I believe the black would cause hotter running temperatures if anything.

I have also heard that painting a radiator makes it not disipate heat as well. So I would guess that not painting an engine, as alot of engines are these days, would be the way to make it run the coolest.

I would be willing to bet money that you will not see a 20deg difference either way, no matter what color you paint it, or whether or not you paint it at all.