sl320 humming sound

[jeffery]

97 sl320 there is a slight vibration up to about 40, then goes away. At about 65 there is a hmmming sound. sounds like right sid. sorry deaf in right ear. any ideas? thanks

[97 SL320]

Is it tied to engine speed or road speed? ( maintain say 40 MPH road speed but down shift a gear so the engine comes up to determine this. )

Have the front wheel bearings been replaced / lubed lately? Mine had a front outer bearing failure at some time in its life ( it had / has 124,000 miles when I got it ).

Poor tire balance can cause this as can a tire that has cupping wear. A square block can be balanced but it won't roll very well.

Past that, it is difficult to remotely diagnose such a problem.

Some data I've come across pertaining to our SL320s ( from the SL market letter )

Number sold in the US 1,653 / Non US 4,835
Retail $ 80,195

For comparison , the SL500 sold US 5,632 / Non US 8,120
and SL600 sold US 740 / Non US 1,164

[jeffery]

Bearing were replaced recently. Will look into the tire balance, and try the downshift idea. Sounds like the 320 is somewhat rare. Thanks for the info

[RadioTek]

Do not ignore the possibility of your flex plates. They are a "wear item" and should be checked out periodically and changed if necessary. If one of them fails, the effect could be 'catastrophic'.

FLEX DISC INFO - Benzworld.org - Mercedes-Benz Discussion Forum

For the gory details.

Scott

[jeffery]

Thanks, will do