1989 w124 260E rattle
 

Greetings,

This is a bit long, but I need to explain a few
things.

I am trying to track down a rattle in my 1989 w124
260E. It is an intermittent rattle. It is not
dependent on speed, temperature, braking or anything
else. I can go 50 miles before it starts. That is
the only thing that is consistent. i.e. if I start
from a cold start in the morning it takes anywhere
from 25-50 miles of driving before I hear it.

The noise seems to come from behind the instrument
cluster or perhaps the center of the dashboard.
I have completely removed the instrument cluster and
speedometer cable and driven the car and it still
makes the noise/rattle. So, it has nothing to do
with the cluster.

I have tried all the heat/AC switch settings and it
makes no difference. I have removed the kick panel
below the steering wheel and checked things to no
avail. I have removed the fuse box and relays in the
left corner of the engine bay near the firewall and
reached back where the wire harnesses are located to
see if anything is loose but that did not do anything
either.

What does the rattle sound like?
It kind of sounds like "delicate wind chimes", only not
that nice or rhythmic. What I'm trying to say is that
it does not sound like something rolling or bouncing
around in the air ducts. It is more of a "floating"
or metal against metal (?) noise.

Here are my current problems:
I gave the car to the dealer for 1 week with the
understanding that they could spend up to 4 hours
looking for it. They assured me that they have tools
to analyze such things. I picked the car up after
a week and they said they never got to it and
basically don't want to deal with it and nothing is
wrong with the car. They also could not guarantee
that after spending their time and my money that they
would find anything.

Does MBUSA have a regional rep. who can reference
technical service bulletins to see if this rattle
is a known problem? I checked alldata.com and
there was nothing that looked like the same
problem.

If the dealer won't look at it, what should I do?
I don't really blame them for not wanting to take
this intermittent problem and "own" it but, now I
can't fix the problem even for $$.

If I were to trade this car for another, the next
owner would come back and complain about this rattle
and then the dealer that sold it would be forced to
do something, am I right? Well, all I'm saying
here is that it has to have a solution and I would
rather be the owner who gets it fixed rather than
selling the car and having the next owner get it
fixed.

Are there any suggestions as which way to go now?
I really don't want to tear the dashboard apart
myself as my time is limited and this is my daily
driver. Perhaps the noise is in the heater motor
area?

Thanks for your time,

Jeff

Jeff,

A couple of questions and ideas:

You said it doesn't depend on speed, but I assume that the noise stops when you stop the car, right? So that would mean that it something related to the chassis motion caused by driving, and not related to engine rpm or drivetrain rpm. First eliminate the relationship with engine RPM by letting it coast in neutral with the engine turned off. If the noise is still there, you've ruled out anything related to the engine running.

How about getting the car warmed up to the point where it's rattling and then getting someone else to drive it while you climb around the interior, open each window and listen for it from different areas? This may help you isolate whether it's really coming from the dash versus the underside, engine compartment, etc.

Is this a repeatable problem, or intermittent? Can you replicate it anytime? If so, take the mechanic for a ride when you can demonstrate the noise.

Hope this helps...

Hi Dennis,

Thanks for the response.

It really does not depend on speed. For example,
if the car is in park in my driveway with the
engine either off or on, I can take my fist and
lightly pound on the top of the steering wheel
and hear the rattle, but only 1 repetition of
the rattle i.e. a single blip of the noise.
I "believe" that I have heard the noise when
lightly "pounding" on the fuse box area too.
In this case also, it is only a single note
and not a "echoing" type of rattle-rattle-rattle.

Also when it /is/ making the noise, I can make it
happen by being at a standstill (engine running)
and releasing the brakes so the car moves only as
much to jerk the body a bit. So my point is that
it can happen under the least amount of movement
(when it wants to).

I have had passengers listen to it including the
dealer and they all agree that it sounds like
it is coming from behind the instrument cluster
area. It may be in front of the firewall, but
nevertheless, that is the general region. I have
played with most everything in the area to no
avail.

As far as being repeatable, yes but only after it
"decides" that it wants to do it. I never know
for sure that it will start making the noise.

Also, when it is /not/ making the noise, and I go
over a rough road (construction, example) it
will /not/ make the noise. i.e. it has to be in
the part of its cycle where it "wants" (for
lack of a better word) to make the rattle.

Another clue: It starts out very quietly and
with only a few noises, then quickly builds to
a louder and more frantic rattle. As far as the
level of noise, consider this: It's about as
loud as a desktop Windows-based PC is when it
is accessing the disk. Maybe a little louder.
So it's not going to make me go deaf, only crazy.

thanks for any other thoughts...
Jeff