The Nissan 350Z uses a tensioner pulley to keep the serpentine belt tight. However, over time, the belt stretches beyond the pulley's ability to keep the belt tight. This causes the belt to squeal when it is cold or on hard accelerations. When the belt squeals, it slips on the pulleys and causes excessive heat to build up in the belt, which could cause the belt to break. When the belt stretches this far, you must replace it with a new one.
Inspect the radiator fan shroud for the diagram that shows you how to route the belt around the water pump pulley, the steering pump pulley, the air conditioner pulley, the tensioner pulley and the alternator pulley. Use the diagram after you remove the belt to show you how to put it back on. If the diagram is missing, make one by drawing the pulleys and the side of the pulleys the belt pushes against.
Locate the tensioner pulley under the alternator. The pulley does not bolt to any component and it has a square hole in the center of it. Place the 3/8-inch ratchet drive into the square hole on the pulley.
Lift up on the handle of the ratchet to loosen pressure on the belt and pull the belt off the tensioner pulley.
Remove the belt from the other pulleys and route the new belt onto all the pulleys except the tensioner pulley. Again, use the diagram to ensure you have the belt routed on the correct side of each pulley.
Pull up on the ratchet handle and slide the serpentine belt over the tensioner pulley. Let go of the ratchet driver handle to add pressure to the new belt.
