Thanks for quick responses, guys.
I took a look during cold startup this morning (30F) ... can push down on base of shock (or top of tensioner ... CD ROM calls the tensioner "tensioner adj.) and it stops the vibration - vibration is very high frequency and resulting sound is a "rattle" with "tinging" vice banging.
The tensioner is original ... the car, in 138K miles, has had at least (counting previous owner) 8 shocks installed ... the ones I have removed have been very "loose" - i.e. easily depressed and extended by hand (new ones going in were pretty tight in both directions).
If I go to the trouble of pulling the shock, and, I know the tensioner is the likely cause of the repetitive replacement of the shock (is this true?), would seem reasonable to simply replace the tensioner, too, right? (seems like price for tensioner was in the $60 range and shock was about $25 ...).
What do you guys think?
1991 350 SDL (200K and she ain't bent, yet)
former 2002 E320 4Matic Wagon - good car
former 1985 300 CD - great car
former 1981 300 TD - good car
former 1972 280 SEL - not so good car
a couple of those diesel Rabbits ...40-45 mpg