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The Wedge - R129 Heater Blower Motor Noise - Temp Broken Strap Workaround
My 97 SL had the blower motor strap broken as many have experienced.
After listening to it howl louder than my wife every time I made a hard turn. 😂
I decided to pull the cover & filter and saw the broken strap. It's pretty tough to get to, and at that point a few years ago, I couldn't commit the time to do the job properly. Not to mention breaking some brittle plastic that may be NLA. Hence this temp hack.
The motor actually sits in a saddle, but only moved for me, on higher G loads / abrupt turning. The more I fiddled with a workaround the more that strap reminded me of a spring. I decided as a temp measure, even with my fat hands, I could get a piece of foam in there and use the strap a with the foams thickness & spring type qualities to hold the motor in place. I told myself as soon as it comes loose I'll do the job right...
Well its been in there for at least 7 years now and hasn't budged! btw I haven't seen anything like this posted, so apologize for the double post and I missed it!
I used a white, multi layer, high density foam. This type of foam is pretty weather&heat resistant and doesn't break down very much over time. I cut a taper into one end in order to be able to engage it easier and there is a vacuum line (green) that it will need to go under. BE CAREFUL NOT TO BREAK THAT LINE when pushing the wedge in.
Your mileage may vary but this seems to have worked pretty well for me at least "temporarily" It may save a few scraped knuckles trying to get to that darn strap.
About 2-1/2" Wide (wide enough go under the whole strap and 1/4 extra on each side)
5-1//2" Long ( enough to get a decent wrap around the motor) The curved strap will sandwich the foam between the round motor making it conform into a semi round shape.
1" thick ( enough to wedge pretty tightly between strap and motor.) Notice the type of foam density.
You have to drop the foam in length wise then rotate it so the tapered part goes in first. Then push it from the back. I used two hands, one in each flap opening, to do this .
The force of the high density foam pushing against the spring keeps it wedged in place. You want to push the foam in so that it's nice and tight, and when properly placed the air flap will be a couple of mm away from the corner of the foam (see below pictures). When the flap is open, even if the foam tries to work its way loose it will press against the flap. It shouldn't need to because if properly placed it will be relatively tight. The flap is locked in that position, and closes in the other direction, so it won't catch the foam. Just push against it.
In the end you can do this hack by just removing cover and filter in a few minutes! At least it will buy you some time and costs almost nothing
Good Luck!
Last edited by crconsulting; 05-08-2021 at 04:03 PM.