Ive been fighting my truck for probably a year now with this, maybe more and i cant figure it out. The truck runs 190-200 empty which is obviously not a problem. The problem comes when you are pulling a heavy load (16-17k lb 5er), accelerating and pulling hills, the temp sometimes just goes out of control before the clutch kicks in and cools the damn thing off. When im towing really heavy it really sucks, its a constant battle trying to keep it from getting hot. Sometimes it will spike up to 230+ so quick that i cant back out of the throttle quick enough and it pukes coolant. It pisses me off because as soon as the clutch finally kicks in it cools right down. Ive tried a mishimoto radiator, new t-stat, new ford fan clutch, 7.3 fan clutch, new ford radiator, no tune, ******** heavy tow tune, 8k tow tune and its all the same. The 7.3 clutch probably worked the best but they never lasted more than maybe a month, always got junk. Is there any way to have the fan clutch start coming in sooner or a more aggressive pwm on it? Ive also thought about switching to evans waterless coolant but damn that **** is expensive and kinda sucks if you ever have a leak and lose some.