To undo the cooling fan and the cooling shroud, first you need to disconnect the drive belt for the accessories, and for 2006 and the later models of the Expedition/Navigator, you also remove the drive belt splash shield. Next, remove the flywheel inspection cover and, with help, jam a large screwdriver into the teeth of the starter ring gear so the crankshaft can't turn. Nut the big central bolt of the crankshaft pulley counterclockwise by using a breaker bar combined with a socket where the crankshaft is held by another person. Remove the crankshaft pulley with a proper puller that screws onto the crankshaft pulley flange; the Woodruff key must remain in the crankshaft keyway during removal. General precaution to be taken should be to ensure that the puller that is used does not cling on the outer flank of the crankshaft pulley. In fitting, apply moly-base grease or clean engine oil on the contact areas of oil seal and at the hub of the crankshaft pulley, before which a small quantity of RTV sealant should be applied at front portion of the key of crankshaft pulley. Put on the crankshaft pulley so that the keyway fits into the Woodruff key, and in case the bolt head is small and could not reach the keyway, use a large washer and bolt to pull the pulley up and tighten the bolt 1/4 turn past the correct torque. The remaining steps, are logically converses of the order of removal. Last of all, check the level of the new oil, switch on the engine for some time and check for any sign of leakage.