How to change the serpentine belt on a 1987 Buick Lesabre?

To change the serpentine belt on a 1987 Buick LeSabre, first, ensure the engine is off and cool. Locate the belt tensioner and use a wrench to relieve tension on the belt, then remove the old belt from the pulleys. Route the new serpentine belt according to the belt routing diagram typically found under the hood. Finally, release the tensioner to secure the new belt in place, and double-check that it's properly aligned on all pulleys before starting the engine.