You want the radiator to be translucent? I've never seen a translucent or transparent radiator, they're designed for heat transfer so they're made of metal since metal's a far better conductor of heat than any plastic. If the radiator were translucent it would have to be made of some sort of glass (too fragile I'd think), plastic or a form of plexi/polycarbonate. Those materials would insulate and make it very difficult to remove heat from the cooling loop. Some waterblocks have a translucent cover, but only on top. The contact surface is again metal.
Sounds like a cool concept, but not really feasible/functional.