W140 Blower Motor Replace
Hi all. Got tired of listening to the screaming squirrel in my dashboard and replaced the blower motor in the heater today.
Car is 1996 S500 Coupe.
Thanks to Phil at MercedesShop, was able to buy just the motor and not the entire blower assembly like Mercedes wants to sell you for big dollars. The original Bosch motor from Phil was less than 2 hundred.
Anyway, after reading the replacement procedure I was thinking it would take me all day... in fact, about an hour.
Bottom line is that most of what the manual tells you to do is unnecessary.
All you have to do is open the hood, and remove the air plenum directly in front of the windshield. There are a half dozen or so large phillips head screws. Take those out.
The plenum will be loose, but don't yank it out. Lift it gently and remove the electrical and vacuum connections underneath.
Remove the plenum and you'll have direct access to the filter for the heater. Remove that and you'll have direct access to the blower assembly. A few torx screws and a little wiggling and it comes right out. The motor/fan is held into the assembly with two torx screws.
Trickiest issue is removing the fan from the motor. Its plastic and I'm sure it will break if you force it too hard. I sprayed some WD40 on the shaft end, held the fan hub, and tapped on the motor end with a drift/mallet. It took a bit of convincing, but it came off easily once it began to move. There are no screws or clips that hold it on.
Now, just put it all back together with the new motor. Makes a huge difference in air flow and its QUIET.
If you've been putting this off because the book makes it sound hard, you don't have to hesitate. Piece of cake.
Hope this helps someone.