Nissan Pathfinder models generally have more than one belt, either two or three drive belts according to models and features. Nissan suggests checking these belts every 6,000 miles or 6 months. The process varies for models with idler pulleys and without idler pulleys. This guide refers to model years for 1996-2004. Though newer Nissan Pathfinders should have identical systems, check your documentation for specific info on your model year.
Check the routing of the belt so you know how to replace the belt. If you can't find a belt routing diagram under the hood, make a sketch for your own reference.
Find the idler pulley that holds tension on the belt.
Use a wrench to loosen the nut in the center of the idler pulley.
Turn the adjustment bolt, located beside the top of the pulley, to loosen tension on the belt.
Take off the old belt and replace it with the new one according to your belt routing diagram.
Tighten the adjustment bolt to replace appropriate tension on the belt.
Make the pulley lock bolt tight.
Note the belt routing diagram under the hood. If there isn't one, make a sketch for your own reference.
Loosen the lock bolt that is situated near the top of the component you are going to move.
Turn an adjustment bolt that moves the component toward the engine to release tension on the belt.
Slip the old belt off and replace the new one according to your belt routing diagram.
Turn the adjustment bolt the other way to replace tension on the belt.
Tighten the lock bolt.
Since the belts share the crankshaft, it may be necessary to remove outer belts to get to inner belts. For this reason, Nissan recommends replacing all of the belts at once.