Whenever talk turns to intercooler colour, two schools of thought emerge. There are those who suggest intercoolers should be painted black to aid heat dissipation. Then there are those who suggest the insulating properties of paint would outweigh any better thermal emissivity the intercooler would gain with its colour change.

I have always thought – and continue to think – that the insulating properties of a very thin layer of paint would be effectively nil. After all, you don’t have much faith in that ‘insulation’ when you’re reluctant to put your hand on a painted exhaust manifold or exhaust pipe!

But what about paints that are designed to insulate? Clearly you wouldn’t put them on an intercooler – but what about the pipe coming back from the intercooler to the inlet manifold? As I wrote in Insulating the Return, measurable gains can be made if engine bay heat is prevented from warming the returning air.

At least two different approaches are taken to insulating paints. The first is where the special paint is bought and simply applied. The other approach is where you mix an additive in an existing paint.

InsulTec is an example of the premixed stuff. The applied paint is apparently so thick that the maker calls it a membrane, rather than just paint.

Insuladd takes the additive approach. The additive comprises tiny ceramic ‘microspheres’ – they’re so small the additive looks like flour. To reduce cabin temperatures, apparently at least one local race car team is using the additive in the paint they put on the firewall.

It all sounds like it could work but clearly the vast majority of experience has been gained on the roofs of buildings. In that application, where the incoming radiation is short wavelength, different aspects of the paint (like its colour) may be more important than the composition of the stuff.

I dunno. But I’d be curious to hear from anyone who has used insulating paint in an automotive application – irrespective of whether it was a success or failure.