Why not anodize aluminum car parts?
 

After cleaning my radiators I had a thought

Why not anodize them to reduce corrosion and make them easier to clean?

And not just radiators, but other cast and machined aluminum parts?

Why not?

Would it reduce cooling capacity or increase it?

Anodizing would actually seem to be beneficial to heat transfer (at least for radiative cooling - which is not really what a radiator is doing despite the name.) Many semiconductor heat sinks are anodized because of improved performance.

However, some alloys of aluminum are easier to anodize than others - for example, 2000 series aluminum (e.g. like the popular 2024) are difficult to anodize. Other common alloys like 6000 series (e.g. 6061) are easier to anodize.

Then, the cost and need come into play. If regular aluminum is holding up just fine, why go to the expense of preparing each article and then anodizing it?

ed