comes & goes. Any fans behind the dash?

Check speedometer cable for lube where it enters speedo head.

thanks rocky, I'll check it out, Jack

Heater blower if the sound comes from the center, air sampler if its on the right, speedo or cable if its on the left

You didn't specify when the noise is happening.

On my 500SL, one of the vacuum pods for the HVAC system leaks. Sounds like someone letting air out of a balloon! A/C doesn't work anyway, so I have that vacuum line blocked off.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)