when im crusing up the expressway at around 70 mph the temp starts to rise above where im comfortable to run it at, the vehical is a 1959 mercury monterey and its all stock and i dont want to modify it. so i was wandering about additives for the coolant that accualy work. water wetter or something like that. does anyone have any suggestions or ideas. it would realy help, as im going on a trip and want to drive it but i dont want to overheat it.