Painting a radiator

I have a new radiator/intercooler assembly ready to go back in my Shelby Lancer. It consists of a TU aluminum radiator, MP Indy intercooler, and a Derale electric fan.

Should I paint the radiator and/or intercooler before putting them in the car? The radiator is still bare aluminum and a lot of the original paint on the intercooler is gone. I was thinking of at least covering the cores with cardboard and giving the end tanks and header panels a coat of paint first so they will stay looking nice.

Good idea/bad idea?

My concern is paint is generally a poor conductor of heat and thus reduce the heat transfer. I have used Silver filled paint for small projects but it is very expensive.

the only reason rads are ever painted is to protect them from rotting instantly
(brass n copper)

aluminum rots a little slower

if your liking the nice new aluminum tanks you could consider finding some clear coat for aluminum

I have no idea how much clear would reduce the effective cooling of the fins but if thin I doubt it would be any worse than painting them black
(which also reduces the cooling although black cools better than polished metal as leaning on your turbo valve covers has probably taught you as the fins and letters are always way way hotter than the black wrinkle - chrome oil pans are a bad idea for this reason)

I see no harm in painting the end tanks, but personally I wouldn't paint the cores.

Coat it with cerakote. I've been wanting to do this when the need arises.

Quote about cerakote
About Transfer Black: C-187
Transfer Black is formulated to provide an increased thermal transfer from a surface to a free flowing air environment. When applied to metal substrates, this coating is proven to increase thermal transfer of up to 35-40% versus uncoated metal substrates. This increased thermal transfer results in components operating at lower temperatures, thus creating gains in efficiency, and extending part life.

Eastwood actually sells a radiator black paint. They claim it's thinner than regular aerosols so it won't plug up the core, and is supposed to transfer heat well.

I haven't personally used the stuff, just putting the info out there. But I do use a lot of Eastwood products, and have been very happy with everything else I have bought.

One tip I gathered along the way is that when painting a radiator and you want to paint the core, just paint the core from the top. That way all the tops of the tubes are covered and look nice when the hood is popped yet still get good heat transfer from the unpainted bottom side of the tubes.

^The guy who re-cored my GLHS radiator told me that as well.