The Nissan Frontier engine uses multiple drive belts, with each belt powering at least one engine component such as the alternator or power steering pump. Over time, the belts will stretch, wear out and become cracked, requiring you to replace them. It is possible to change one belt, but there is a good chance you must replace them all at the same time. The exact process might vary depending on the Frontier's age and engine type.
Check the belt routing diagram, which should be printed on or near the radiator shroud. This will show you the exact routing path needed for each individual drive belt.
Loosen the idler pulley for the individual belt using a wrench or breaker bar on the pulley nut and slide the belt off all the pulleys. If there is no idler, loosen the bolts for the belt's engine component and move the component within its bracket.
Slip the replacement belt onto all of the pulleys, making sure you follow the correct path, and either tighten the idler pulley or the component's position to tighten the drive belt.
Push down on the belt with your thumb at a center point between two pulleys. If the pulleys are between 7-11 inches apart, the belt should deflect by a quarter inch. It should deflect no more than a half-inch if the distance id 12-16 inches.
Adjust the tension of the belt if needed using the idler pulley or component.
