86 300E - Bad Blower Motor?

[Phalcon51]

A couple of months ago, my blower fan started to make a muted noise (sort of a rapid tunk-tunk-tunk-tunk-tunk) whenever the fan was set on low speed. At high speed, it just blends into a kind of low-volume drone. It sounds like the squirrel-cage is hitting something every time around. Lately, it will run when the car has been sitting overnight or for several hours, but once I run it for 10 or 15 min. and shut it off, it won't come back on again, as if it's binding from heat or something. Is this a typical failure mode for a blower motor? Do the squirrel cages themselves, being 19 year-old plastic by now, ever self-destruct? Seems I've read posts complaining of screeching noises from bad bearings/bushings, but I haven't come across a description of this problem.

Is the fan/motor relatively easy to extract? Approximately how much time might it take? Can anyone point me to a how-to or DIY article. I don't want to order parts until I know exactly what the problem is.

Thanks

[Phalcon51]

Anybody?

[Phalcon51]

Still looking for help and advice with this problem

Thanks

[rschleicher]

Phalcon51,

I've done the blower motor replacement on a 1991 W126 (420SEL), so it may not be identical, but it is probably similar. In my case, the location of the blower motor is up above the footwell area for the front passenger.

My symptoms were that the motor first started to make some ticking sounds, and seemed to be running slow. I removed it, cleaned/oiled the bearing area, thought about cleaning/filing the brushes, but didn't see any easy way to remove them. So, I put it back in, and it ran OK for a few more months. Then it gave up the ghost entirely. I bought a replacement motor, without squirrel cage, since it is quite a bit cheaper without the cage.

removal/replacement is pretty straightforward. In my case, I had to carefully pry out a trim piece, to get access to the screws that hold in the padded knee bolster. Then, there are a few screws to remove to allow the plastic cover over the motor assembly to drop down. This cover also has the so-called "porcupine" assembly on it, and also has some wired going to it, so you need to gently move it to the side while you unbolt the actual motor and squirrel cage. Remove the two wires to the motor, and it's out.

Separating the squirrel cage from the motor takes a bit of banging, as it is a tight press fit onto the end of the motor shaft. I found that setting the squirrel cage on top of a solid support, but with an opening in the middle of the support so that the actual motor can hang suspended in the opening, allows you to use a nail set (or even a Phillips screwdriver, in a pinch) to pound on the end of the motor shaft, through the little hole of the squirrel cage mounting area. You really have to bang on it to free it - a little Liquid Wrench or other penetrating oil might help. The trick to not breaking the squirrel cage is to have it evenly supported around the perimeter of the cage - otherwise the plastic is pretty brittle and you can easily crack it.

Good luck!

[cangold]

In the 300 E the blower motor is under the wiper motor you have to remove it ...check the forums ...they are great...also try ebay and you can get a used one with cages well under the $300 price tag

[brewtoo]

Yes, on the 300E the blower motor comes out from the TOP OUTSIDE.