In my opinion, the suggestion offered by rdanz is very bad advice, and a real good way to lose a finger or two! The squealing is most likely caused by the belt slipping on the alternator pulley when it has a heavy charging load right after the car is started. Replace the belt, or have it replaced. If the tensioner has gone bad, replace it also. Don't fool around under the hood with the engine running! Too many rotating parts that don't care about your one-time-only limbs!!
'82 300D/4.3L V6