Open the hood of your Saturn. Locate the negative battery terminal and remove the bolt from the negative battery cable that is on the terminal with a wrench. Lift the battery cable off the terminal and tuck it out of the way so it can not fall against either battery terminal while you are working.
Look at the front of the engine block and find the serpentine belt tensioner on the engine. Place a socket on the nut in the center of the tensioner pulley and then attach a breaker bar to the socket. Rotate the tensioner clockwise using the breaker bar and socket and then remove the belt from the pulleys.
Rotate the tensioner counterclockwise and allow it to rest in the free arm position. Install the new belt around all the pulleys except the tensioner pulley. Be sure you follow the diagram in the owner's manual or under the hood for the correct path over the pulleys. An incorrectly installed belt can turn the accessories in the wrong direction, damaging them and allowing the engine to overheat.
Turn the tensioner clockwise with your breaker bar and socket and next install the belt over the tensioner pulley. Slowly return the tensioner to the home or free arm position. The tensioner will tighten the belt to the proper tension as you rotate it back so do not force the tensioner back. When it stops, leave it where it is.
Replace the negative battery cable on the battery terminal. Install the retaining bolt then tighten the bolt with a wrench until it is secure. You do not need to tighten to0 much--just until it is snug. Close the hood of your Saturn and recheck the belt in a few days to make sure it is still running over the belt properly and the tensioner is adjusting, as it should.The 2000 Saturn LS uses a serpentine belt on the front of the 3.0-liter V6 engine used that year. The car is available with a four-cylinder as well but that engine uses several belts, not a serpentine system. The 3.0-liter engine has the belt tensioner on the upper left side of the engine, as you stand looking at it. It sits directly above the alternator and access to it is extremely good. This is not the case in many cars so it allows the home mechanic to change the belt without any specialty tools.