Ford 2003 Mustang Workshop Manual page 1572

62. Install the crankshaft pulley and tighten the bolt in four stages.
Stage 1: Tighten to 90 Nm (66 lb-ft).
Stage 2: Loosen the bolt one full turn.
Stage 3: Tighten to 50 Nm (37 lb-ft).
Stage 4: Tighten an additional 90 degrees.
63. NOTE: Lubricate the O-ring seal with clean engine coolant.
Install the water pump.
64. Install the water pump pulley and the bolts.