The Prius model vehicles come equipped with a poly-v ribbed belt that controls all of the front engine accessories. The v-shaped belt travels inside all of the accessory pulleys. When the engine is running, the crankshaft turns the belt around each accessory pulley at the same time. As the belt is traveling around each accessory pulley, it enables the accessories to function. Replace the belt as soon as possible if there is any type fo damage or excessive cracking anywhere on the belt.
Park the Prius and open the hood. Turn the motor off and apply the parking brake.
Slide under the front end of the Prius and locate the engine cover between the radiator and the engine. Remove all of the bolts from the cover with the ratchet and a socket. Then, pull the cover down and slide it to the side.
Remove the air cleaner inlet tube from the air cleaner housing by unscrewing the band clamp with a flat head screwdriver. Pull the inlet tube off and set it to the side.
Locate the adjustable idler pulley on the upper right hand side of the crankshaft pulley. The adjustable idler pulley is the component that tensions the belt. Loosen the bolt in the center of the idler pulley with the ratchet and a socket.
Locate the adjustment bolt on the top of the idler pulley. Loosen the adjustment bolt by turning it counter clockwise with the ratchet and socket. Once the belt is loose, remove it from the idler pulley and the other pulleys. Then, pull the belt out through the bottom of the engine compartment.
Route the new belt through the bottom of the engine compartment and onto the crankshaft pulley. Then, route the belt into the other pulleys.
Tighten the belt by turning the adjustment bolt clockwise with the ratchet and socket. Once the belt is tight, check the tension of the belt with your hand. If the belt has more than a half-inch of slack, then the belt is too loose. Continue to tighten the belt until there is a half-inch of slack in the belt.
Tighten the locking bolt in the center of the idler pulley tight with the ratchet and socket. Inspect the belt to ensure that is is properly seated inside of the each pulley. Then, crank the Prius and allow the motor to run for about twenty seconds Turn the motor off and recheck the tension on the belt with your hand.
Reinstall the air cleaner inlet tube and the bottom engine cover.
