sorry, but u are wrong. copper displaces heat faster. A/c systems did have copper evaporators. The ones built a long time ago, had copper cores and aluminum fins. The aluminum fins made it lighter. The reason they went to aluminum is because of high cost of copper. Copper just tranfers heat better. if U don't believe me, ask an Aluminum Ratiator manufacturer. They will tell u copper displaces heat better, but the way they build aluminum radiators, makes theirs more efficient. But ,(i'm not positive on this, so don't hang me), the alum. radiators in the newer trucks are built like the cooper ones, meaning that the tubes are small. So, this is my thinking, if we had aluminum radiators (custom) built for our trucks, then it would cool better, but a huge cost, but the factory aluminum comparred to the factory copper, i think the copper is better, being of the poor design of our aluminum radiators.