The Toyota Sienna engine incorporates a serpentine belt that runs all of the different engine accessories. The serpentine belt connects to the engine's crankshaft and drives the the power steering and the water pump, as well as the air conditioner and the alternator. An adjustable tension pulley ensures that the belt is tuned to properly drive the various accessories.
Open the hood, and secure it in the upright position.
Examine the serpentine belt and the pattern it follows around the various pulleys. Make sure that you have a diagram in the owner's manual for your vehicle. If necessary, make a sketch of the belt's pattern, or take a digital photograph you can refer to when threading the replacement belt.
Fit a half-inch socket onto the nut on the front of the tension pulley. Turn the nut left to loosen the self-tensioning pulley. With the pulley loosened, remove the old serpentine belt.
Compare your old serpentine belt with the new belt. Check that the length and the number of teeth on each belt are the same.
Refer to your diagram or photograph, and thread the new serpentine belt around the pulleys and over the tension pulley. Use your socket wrench to loosen the self-tensioning pulley enough to allow the serpentine belt to fit around it.
Allow the self-tensioning pulley to shift back into position by releasing the pressure with your socket wrench.
Disengage the socket wrench from the self-tensioning pulley. Check to make sure the serpentine belt is seated properly around the pulleys.
Close and secure the car's hood.
