How to Change the Serpentine Belt on a 1990 Lexus LS400
- 1). Open the hood of the car and locate the serpentine belt routing diagram. The belt diagram on the 1990 Lexus LS400 is located on top of the fan shroud. The diagram is a picture of the serpentine belt being routed around the pulleys. You will need this diagram when routing the new serpentine belt. If you cant find the diagram, take a notepad and pen and draw the exact routing of the belt around the pulleys.
- 2). Locate the serpentine belt tensioner on the front of the engine. The serpentine belt tensioner on the 1990 Lexus LS400 is located on the front passenger side of the engine. The belt tensioner is above the crankshaft pulley. This controls the tension of the serpentine belt. There is a 15 mm bolt head in the center of the belt tensioner. Place the ratchet with the 15 mm socket onto the bolt head in the center of the belt tensioner.
- 3). Turn the belt tensioner clockwise to relieve the tension from the belt. Slide the serpentine belt off of the top of the belt tensioner pulley. Finish removing the belt from the remaining pulleys. Remove the serpentine belt from the engine compartment.
- 4). Route the new belt around the bottom crankshaft pulley first. Then route the serpentine belt over the remaining pulleys as directed by the serpentine belt routing diagram on top of the fan shroud. Leave the belt tensioner pulley for last.
- 5). Turn the belt tensioner clockwise again and slide the new belt over the top of the belt tensioner pulley. Release the belt tensioner and it will take the slack out of the serpentine belt. Make sure that the belt is completely seated in all of the pulley grooves.
- 6). Start the engine and inspect the serpentine belt again to make sure that the belt stays seated in the pulley grooves while the engine is running. Turn off the engine and shut the hood. Job complete.