How to change serpentine fan belts on 2004 chevrolet tracker zr2

Question edited for clarity.
Question moved to sub category.

You order them to the vehicle, not by size. The three belts are here with the OEM Parts numbers. Parts suppliers have a book with all the makes, models and years, and that book tells them the length, width and form, (ribbed or plain).
https://www.partsgeek.com/catalog/2004/chevrolet/tracker/drive_belts/accessory_drive_belt.html

You can also pick them up from Walmart, or eBay.

https://www.google.com/search?q=2004+Chevy+Tracker+LT+2.5L+V6%2C+serpentine+belt+size

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Hope this helps

If you mean the serpentine belt, this ought to be the answer.

02 Chevrolet Tracker Serpentine Belt Replacement 2002 Chevrolet Tracker...

Go under the vehicle and check the four wheel drive linkage.

bring it to an auto parts store-they can help titen it at the tensioner--may need a new one

GM use a particular item on one of the idlers
there will be a 1/2" square hole in the center of it
use a strong bar and lift the pulley up against a spring
install the new belt and when properly installed let the pulley back onto the belt

It is either bolted in place or it has a spring that can be released with a belt tensioner tool you get at an auto parts store. You might can use a 1/2" brakeover bar.

First, keep this diagram around as you will need it to route the serpentine belt when you reinstall it. There may also be a diagram under the hood by the radiator.
Next, follow this link and watch the video that shows you how to replace a serpentine belt...
http://www.wonderhowto.com/how-to/video/how-to-inspect-and-replace-your-car-s-serpentine-belt-267229/

you mean serpentine belt it should be right in front of the engine right behind the fan

My sincere apologies for the delayed response.
I am personally going back to answer your unanswered questions.
I have only been a free contributor to this site for the past 4-months.

I do not know if you still need this information, but I am going ahead and answering it anyway.

CLICK on the following LINK. It has several Belt Diagrams, one which will match your specific engine and options (AC/No AC, Power Steering, .etc) that you will need.

Regarding HOW:
Standard Rule to Removal the Serpentine Belt:
1. Find the Tensioner(s). (See the Diagrams on Link)
2. Using a Serpentine Belt Tensioner Tool or Wrench or Ratchet Tool: Rotate/Move the Tensioner Pulley/Arm away from contact with the belt and towards the area where the belt is not in contact with the Tensioner Pulley. The Tensioner is spring loaded, and is hard to rotate/move.
3. Remove the loosened belt off one of the other more easily accessed Pulleys.
Standard Rules for Installing the Serpentine Belt:
a. Pick a Pulley that is most easily accessed. This will usually be on top. This will be the last Pulley that the belt will go on.
b. Using the Diagram: Install the new Serpentine Belt on the remainder of the Pulleys....over, under, left right etc.
c. Using a Serpentine Belt Tensioner Tool or Wrench or Ratchet Tool: Rotate/Move the Tensioner Pulley/Arm "away" from Belt contact area on the Tensioner. This spring is pretty hard and with a new belt, it will be even harder to install. Rotate/Move this to as-close to the maximum ("open") allowed inorder to have enough slack in the belt to get it up and over the last pulley.
d. While keeping the Tensioner Pulley/Arm "open" Using your other hand - Pull the Belt up and over the Last remaining Pulley.
e. Before releasing the pressure on the Tensioner, visually inspect the remainder Pulleys and the Belts' Positioning on them.
As you can see in the last Diagram on this Link: there are three (3) Bolts for the FAN Belt that must be loosened inorder to successfully remove this Belt

Let me know if this helped...
Again my apologies..

http://www.2carpros.com/car_repair_information/year/2004/make/chevrolet/model/tracker/2004_chevrolet_tracker_drive_belt_routing_diagram.htm