Date registered: Nov 2007
Vehicle: W140 Mercedes 500 SE, 1992, European, 400.000 km
Location: Slovenia (Europe)
Mentioned: 0 Post(s)
Quoted: 207 Post(s)
you must check the blower (fan) itself. it is easy, only 6 screws to remove. search this forum for "blower" or "cabin filter" and you will find instructions how to get access to the blower. most probably all four screws of the blower are losen and the fan touches something. Or maybe something else is going on, it is almost impossible to guess.
All I wish for Christmas is a smooth idle.