You should be able to find a shop manual at your local library with the right info...make copies as they are usually only in the REFERENCE section....good luck:)
How to replace the belt
changing serpentine belt and pulley 90' sedan deville
Serpentine brote change
Use a socket and ratchet and place on the 95 Deville's belt tensioner pulley. Pull to the side to release tension on the belt. Remove the belt and replace it, then lower the pulley back into place.
loosen the tensioner bracket, remove old belt. replace with new belt. tighten with tensioner. job complete!
chain
Chain.
Timing Chain.
Same exact thing happened to my '96 cadillac deville just last week. The belt actually shredded. If you look at the location of the belt (right at the lower right corner of the engine) you may decide you may not want to mess with it yourself. I didn't. I took it in to Firestone and they fixed it parts/labor for $60
The cam on this engine is driven by a CHAIN and not a belt. Therefore, It has no timing belt.
How Do I change the serpentine belt on a 1989 Cadillac Eldorado ?
i am not to keen on thos models but you eather pull back on the alternator or with a braker bar, pull back on the tentioner & hold while removing the belt.