I added a fan shroud and cut out part of the inner fenders at the same time I added the louvers, so the engine temp did go down considerably. Also noticed a big difference in the under the hood temp, you can actually feel the heat coming out the louvers when you put your hand over them. The reduced heat also makes it nicer in the cab, before these latest mods it felt like the heater was on all the time, especially when the side vents were open. Now when the vents are open you can actually feel cool air coming in