Thanks, moedip; at least for my mechanically basic mind, that's the clearest rundown I've seen on what to expect if it is indeed healthy. Based on that, I'll double check but may well try replacing it (which appears to be within my skills--four simple bolts and transplanting the fan to the new drive, is it not?). I'm not overheating or even close, but the sound is mildly annoying to a mildly obsessive owner.
'97 SL500, 40th anniversary edition
'04 Olds Bravada (SWMBO's)
'06 Lexus ES330
'89 560SL (sold)
SL--Anything else is just a Mercedes.
(Kudos to whoever said it first)