Mist the air before it goes into the radiator? Have you ever felt the air draw of a big diesel radiator fan at full throttle? Along with the outside air flow from a moving vehicle? It might mist when you are testing it but it is going to be drops when you are driving. That is why I just drench the radiator-- it works.
So does that mean driving in the rain makes the bus run cooler...?
Rain is a definite misting system that works. It also works on patios. However, on my bus we will continue to spray 'till the water runs out!! BTW, my bus never overheats, even up the worst grades, unless I am pulling a trailer or vehicle. A couple of weeks ago I pulled a 7,000 trailer loaded with 5,000 lbs. of steel building up 4,000 feet frpm Phoenix. The temperature never got past 190 with the sprayer, and it was 101F that day.