Q: How to diagnose and replace a failed fan clutch and Engine Cooling Fan on Lincoln Navigator?
A: Symptoms of failure of the fan clutch include continuous noisy operation, looseness, vibration, and evidence of silicone fluid leaks. On 2007 and later Expedition/Navigator models, check for codes related to the electronic fan clutch system using a scan tool. Rock the fan back and forth by hand to check for excessive bearing play. With the engine cold, turn the blades by hand to ensure the fan turns freely. Visually inspect for substantial fluid leakage from the fan clutch assembly, a deformed bi-metal spring, or grease leakage from the cooling fan bearing. If any of these conditions exist, replace the fan clutch. When the engine is warmed up, turn off the ignition switch and turn the fan by hand. Some resistance should be felt. If the fan turns easily, replace the fan clutch. To remove and install the fan clutch, start by disconnecting the battery cable at the negative battery terminal. Remove the air cleaner assembly and, on 2007 and later Expedition/Navigator models, remove the screws securing the underhood fuse/relay box to the fan shroud and set it aside. Drain the cooling system and remove the plastic air deflector over the Radiator. Remove the upper radiator hose and the degas bottle from the left side of the radiator, disconnecting the hose connected to the radiator. Use a special two-part fan wrench set to remove the cooling fan assembly. Hold the water pump pulley with the clutch-holding tool and an extension while turning the clutch nut with the longer tool. Note that on some models, the fan clutch hub nut is left-hand thread. Unbolt the fan shroud and lift the fan assembly and shroud out of the engine compartment together. The fan clutch can be unbolted from the fan blade assembly for replacement. Installation is the reverse of removal.