There is no diagram for replacing my broken serpentine belt on my 1996 regal 3800

The tensioner should adjust and take the correct belt and tension it correctly. The reasons for belts coming off and worn / loose belt, wrong belt, tensioner not working, or incorrect belt alignment.

https://www.google.com/search?q=1996+buick+regal+custom+serpentine+belt+alignment

Easy job on those vehicles. Usually need a wrench that fits over the belt tensioner, and you raise or lower it, taking tension off the belt. then just slip it off the nearest pulley-often the alternator pulley. Now you can let go of the tensioner and remove belt. Notice how it is fit. There should be a diagram on a sticker of how the belt fits on.

there should be a decal under the hood somewhere that shows the belt routing. if its gone you can probably go to the library and find a book of your car that will show the routing and you can either draw a picture or take a photo of it.

Go to this web site.

http://www.greatautohelp.com/How-To/Replace-3800-V6-Belt.html.

There is a good diagram of the belt routing.

Go to this link and you will find the diagram your lookiing for. Count the belt contact points(pully) and notice where they are. http://www.paulstravelpictures.com/GM-Pontiac-Grand-Prix-Serpentine-Belt-Replacement-Guide/GM-3800-II-Serpentine-Belt-Replacement-Guide-003.html

should be a diagram under the hood of the car.

the broken pulley is more than likely the cause of the break and yes you need it or you can do more damage

need to see diagram for serpentine belt installation on 19991 buick lasabre

how to change serpentine belts on 1996 olds lss

You need to remove the mount, no other way to get the belt on, Labor time is over 1 hour for someone that has done them before.