1989 w124 260E rattle

[atombaum]

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