Truck --1990 chevy 3500 4x4 454 auto,,air if it matters. Just got a free uni-mount western 7'6" footer. Truck overheats like mad. Don't matter if the blade is an inch off the ground or all the way up. I changed the thermostat went to a 180* still no help. Do they sell a straight fan for this thing ?? i think the clutch fan stinks or do i have other probs ????