since i've never seen a steel radiator before, i'll assume you have a copper/brass radiator.. copper/brass sheds heat better, but an aluminum rad can have larger tubes with more surface area that more than compensates for that. so, i'll say an aluminum radiator will cool better than a copper/brass one of the same size.
To achieve the right engine coolant flow rate, the experts at Griffin Radiator recommend restrictions in the engine and good flow in the radiator. Create restrictions in the engine by using
We have found that the 'red' coolants, such as Dex-Cool and Toyota's Long-Life coolant, can clog our radiators, as well as promote leaks. We recommend the traditional 'green/yellow' coolant from most name-brand manufacturers, and to mix that coolant with distilled water at a 50/50 ratio. Most any of the red/orange/pink coolants, and some of the
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