Well there goes that idea!
There's a bloke in Bendigo that makes up 4 core copper rads for the D1 .. had it in mind to try to get one for mine considering the heat mine generated with the A/C on last summer.
I would have thought with a 4 core rad .. you'd be hard pressed to be getting any heat in the engine.
Apart from a possibly weak water pump(ie. broken impeller blades or some such thing) .. I'm out of ideas for 'ya.

