My 84 gt has a loud roaring sound above 2500 rpm's, the mechanic that I have do all the work on both my cars says its the fan clutch. I'm going to go get the part tomarrow but I need to know if it is thermal or non-thermal. I've never dealt with a fan clutch before, I dont even know what it is but I'm sure I can change it out. What are some pointers that I need to know to change this thing out. Thanks in advance.