We can mount the fan drive assembly either directly on the water pump hub or on a hub/bearing attached to the right front side of the engine aluminum bracket. Loose all four nuts responsible for holding the fan to the mounting but don't remove them yet. After that, remove the accessory drive belt. Certain engine types may need the fan shroud removed to take out the viscous fan drive which should be removed with the fan blade. After taking away the four screws holding the fan system, remove the assembly from beneath the vehicle. Store the thermal viscous fan drive vertically to stop the silicone fluid from leaking into the bearing assembly and spoiling its lubrication. Use mild soap and water to clean the fan blades, but don't use anything hard like a brush. If the fan blade assembly is not within spec, do not attempt to bend the blades until an expert looks at them. In the event that the assembly is swapped out because of mechanical problems, you should check the water pump and viscous fan drive for harsh vibration damage. Loosen four bolts to remove the fan blade from the viscous fan drive unit, then lay the fan with its leading edge on a flat area. Should the space between the blade and the surface go over 2.0 mm (0.090 inch) or the rocking motion equal 2.0 mm (0.090 inch), change the replacement fan. Any cracks, loose rivets, bends or broken welds in the fan assembly means it should be replaced. Following installation of the fan drive, speed up the engine to 2000 rpm and hold for around two minutes so that all fluid is distributed as it should be. Put the viscous fan drive onto the fan blade and tighten the bolts to 24 Nm or 18 ft. lbs. Put the mounting flange of the fan blade/viscous fan drive assembly onto the hub, insert all four nuts and tighten to 27 Nm (20 ft. lbs.), first tightening the first two and then the last two. It's important to fit the serpentine accessory drive belt correctly so that the water pump rotates in the right way and the engine stays cool. After that, mount the accessory drive belt.