How does one replace the serpentine belt on a 2004 toyota avalon?

SOURCE: how to remove the serpentine belt of a 2004 toyota

Actually you don't have to do all of that. I just replaced one from the top. On the passenger side of the engine where the belt is, you will see the tensioner in the middle. Using a larger breaker bar with the socket that fits the bolt in the middle of the wheel, force the tensioner toward the front of the car to release pressure to remove the belt. I think it was a 15mm but can't remember for sure. I do know they are all metric sizes on that engine. The tricky part is to remember how the belt is routed. If you forget, see the diagram below. There isn't much room to work, but I'm proof that it is possible. When putting the new best on, route all pulleys and leave the alternator for last since it's right on top and easy to get to. Good luck and be patient. It's doable.

SOURCE: how to change serpentine belt, 2004 Toyota Tundra

locate tensioner pulley; release tension from belt; remove belt; make sure not to forget how the belt is routed; route belt around all pulleys but tensioner; put tension on tensioner pulley; route belt over tensioner pulley

SOURCE: Replaciing serpentine belt on 2006 Toyota Corolla

You'll have to remove the engine cover under the bottom so you can position the new belt on the pulleys properly. Get a wrench or tensioner tool and turn the tensioner clockwise to relax the drive belt. Don't apply excessive force.

It's hard to draw a picture with words, but looking at the engine from the passenger side of the car, there are basically two top pulleys, two middle, and two bottom. The drive belt goes around the outside of the two top and two bottom, and on the inside of the two middle.

SOURCE: diagram for 2004 toyota serpentine belt

I have to find out how to send you a picture, I can't do it on here for some reason. if you want give me your e-mail address and I'll send it to you.

SOURCE: i need help getting the serpentine belt on my 2004 Rav 4

SOMETIMES THE DIAGRAM IS ON THE UNDERSIDE OF THE HOOD. OR ON THE WHEEL WELLS INSIDE THE ENGINE COMPARTMENT. CHECK UNDER THE HOOD ANYWHERE A STICKER COULD BE. IT MIGHT ALSO BE IN THE OWNERS MANUAL.