[Mgs] Repair or replace Radiator?

[David Ambrose]

Aluminum and brass are both good heat conductors. In point of fact, 
aluminum conducts heat much better than brass, though not as well as 
copper. All other things being equal, an aluminum radiator should be 
better than a brass one.

However, other things are rarely equal. I suspect the big determinate in 
clean radiator performance is the heat transfer from the radiator to the 
air. The temperature gradients are not that huge, so the heat transfer 
is probably limited by the physical design more than the construction 
material. There are probably a few things you can do with aluminum 
radiators that you can't do with brass. Extruded tubes come to mind, and 
that will certainly make a big difference.

The only way to know with any certainty is to measure the temperatures 
going into, and coming out of, the radiator.

Cheers,
Dave