That sounds like an old belt and as long as they are, you will notice a LOT of stretch if you hold it up to a new one. It might also be the time to replace the tension spring and shock/damper (that work along side each other) at the black tensioner lever. When those are bad you hear a louder chirp like sound.

With the engine running, push down on one side (then the other) of the lever. If it gets quiet - problem defined.

BTW you CAN get a new belt in without removing the fan or a single pulley but you will need time and the patience of a Zen master.

__________________
1987 300D (230,000 mi on a #14 head-watching the temp gauge and keeping the ghost in the machine)
Raleigh NC - Home of deep fried sushi!