I am trying to replace the serpentine belt on a chevy lumina 1996, cannot find a diagram to be sure I am putting it on correctly. any suggestions

Usually it takes a special tool or a crowbar to take the load off the tensioner to remove the old belt and install the new one. Make sure you have a diagram of the belt routing before you take the old belt off.
There should be videos on Youtube for GM engines.

http://www.2carpros.com/diagrams/geo/tracker/2002

Remove the old belt
Measure it
Convert to metric
Go to Auto Parts Store-buy correct belt

It will have a diagram right above the fan blades to show you how it needs to be ran. Just need to release some pressure off the belt tensioner to make it all fit

http://www.mvreader.com/multiview/dayco/zoom.php?zoom_item=C0001J&l=&catalog=auto&category=2

The web link should take you to a diagram of the serpentine belt. Hope it helps!

Diagram should be under the hood
The auto tensioneris down low and dificult to get to.
If it has not been changed in a while you will need a long thin push stick and a serpentine tool.
Push on the belt hard at the auto adjuster and pop the belt off the smooth pully (located top).
hook up the serpentine belt tool and then mount the new belt

diagram should be on the radiator shroud / top of radiator

Check the underside of the hood! You'll laugh!

what i do is draw me a diagram before i take the old belt off you can also ask the auto part store where you get the new belt and for the most part they have a diagram for a long time came on the box with the new belt in it.

Click on the following free direct Link. It has the correct Serpentine Belt Diagrams for your 1996 Chey Tahoe 5.7L depending on your Engine Options (AC/No AC etc.).

Let me know if this helped, or if you have additional information questions. Feel Free to contact me at FixYa.com!

http://www.2carpros.com/car_repair_information/year/1996/make/chevrolet/model/tahoe/1996_chevrolet_tahoe_drive_belt_routing_diagram.htm