Serepentine bels do not have tension adjustments, there is a tension pully That is preloaded with a coil spring in it. If the belt is loose, the pully spring may have lost it tension. Replace the pully assembley.
There is no tension adjustment. Tension is automatically adjusted by the idler pulley.
replace tension put it on
There is no adjustment for ignition timing.
there is a rattling noise in the area of the serpentine bell
no its driven by the serpentine belt
There is a special tool I saw in a pawn shop that is just for that.
Old age Frozen or misaligned pulley
To change the serpentine belt on a 1987 Buick LeSabre, first, ensure the engine is off and cool. Locate the belt tensioner and use a wrench to relieve tension on the belt, then remove the old belt from the pulleys. Route the new serpentine belt according to the belt routing diagram typically found under the hood. Finally, release the tensioner to secure the new belt in place, and double-check that it's properly aligned on all pulleys before starting the engine.
I had a 1995 buick lesabre and the A/C compressor went out in the winter time. I waited until spring to replace the compressor. In the mean time, I used a Dayco 72.10 inch belt and bypassed the A/C compressor and it runs fine.
put a wrench on the tensioner pully and pull it to release tension on the belt
with a 9/16 socket and ratchet
Because its a 1988 Buick LeSabre