First of all: Happy Holidays to all. I would like to know what the difference is between fan clutches, if any and or does it make a difference? I seem to have a lot of fan noise going down the road. What is the difference in water pumps? I have three different styles. What is the difference between a 383 and a 413 ? Give me a cooling system class 101.. Thanks in advance Bob >From the barn in the Mountains of NM. [Non-text portions of this message have been removed]