I was at my mechanic's shop last night and he noticed that my belt tensioner shock has broken loose from one of its mounting points and needs to be replaced. I ordered the replacement today but I’m wondering, what is the function of this shock? My friend said that without it, when I accelerate I may get a rumbling sound. And, in fact, I’ve had this sound for a while.

Thanks

------------------
1985 190e 2.3 5spd
98 E320 rims + TV & VCR
1991 Mazda Miata
1991 Yamaha FZR1000
1994 MB S420 (sold)
1994 BMW 318ica (sold)

I expect that the shock is necessary to prevent belt slippage under certain conditions. There is a sensor system that will shut down the a/c if slippage is sensed. Because the damper prevents impact in the belt tensioning, I expect that it goes a long way toward preventing this problem under certain conditions.

It sounds like it's time to check the tensioner, pulleys, bearings and everything else accessory related, replace what is needed and maybe install a new belt.

Good luck,

------------------
Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

Do a search on the board with the words "belt tensioner". You'll find numerous references to the shock and its' function.
If I remember correctly, it takes up / damps quick motion and directional changes when you put your foot down on the loud pedal or when you let off suddenly.

------------------
Jay Yambrovich
1989 300 E
1992 190-E 2.3