If lubing the blower doesn't make your noise go away, it's fairly easy to take the blower apart for a complete cleaning. I found mine to be rather dirty. It seemed to do a better job of pulling air after cleaning out the dust and lubricating the bushings.

Early versions of the W124 attached the little fan to the under-dash panel on the passenger side. The panel acts as a drumhead and amplifies the sound that the little blower makes. Later W124s attached the blower to the heavy-gauge tubing cross-brace that runs across the cabin behind the dash. In this position, the blower can no longer be heard. A DIY with pictures is posted on this forum here. The bracket could be fabricated with a piece of strap or search the junkyards for a later-than-1987 model.

Jeremy

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970