Fan clutch replacement guidance and recommendations

Generally speaking, running hot at speed is a water flow issue and running hot at slow speeds or at stops is an aif flow issue. You can throw the fan in the ditch runnin down the road at 50 plus MPH. I would be looking at the thermostat, water pump and the overall condition of the water jackets in the engine. Also as someone mentioned, the lower hose collapsing is another thing to look at. Squeeze the bottom hose when it's cold with no pressure. Does it squeeze really easily? That's the suction side of the pump and if the hose is all squishy, it's likely being sucked closed at highway speed. Make sure the thermostat is working properly. Remove it. Put it in a pan of water on the stove with a thermometer. Make sure it starts opening at or before the marked temp on it. It should be fully open by the marked temp. With the thermostat removed, this is a good time to back flush the system and see if there's a lot of crap in it. Remove the lower hose from the water pump and blast water in from the thermostat housing on the intake. The backwards flow can sometimes break junk up and it will come out the water pump inlet. If you see murky or brownish red crap, then you need to properly flush the whole system, including the radiator. Also, check the fan speed in relation to the crankshaft speed. Measure the crank pulley diameter. The water pump pulley diameter should optimally be a little smaller, allowing it to spin faster than the crank pulley. This will allow the pump to spin at an optimal speed to pump coolant out of the hot engine quickly. That's the whole ball of wax with the cooling system. To get the coolant OUT of the engine as quickly as possible and into the radiator so it does not have a chance to get too hot. This business some talk about of slowing the coolant down so it stays in the radiator is hooey. Get it OUT of the engine and into the radiator as quickly as possible.