An update -
I was on my way to work, planning to stop by Silver Star Motors to get Herr Fuch's opinion on the noise this morning, with a stop at the dealer to pick up a part for the '73 280C. About two blocks from the dealer the serpentine belt started making a godawful squeal below 1500 RPM. I decided that discretion was the better part of valor and pulled into the service department for help.
Should have some news shortly, but it looks like something to do with the tensioner.
Thanks to all,
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe