Elusive rattle inside dashboard

[gandalf1]

I’ve got an ’06 B9 with 48k on it. Bought used about 1 year ago. Great, great vehicle.

Recently a rattle has developed in the dashboard, though, that I cannot seem to find the source, and it’s driving me nuts. I figured I would ask folks on this board for their thoughts.

First, the sound itself: the sound is a definitive “rattle” that sounds like something is loose and vibrating around. It does not seem to be a strongly metallic sound, although it’s not a dull, muted, or muffled sound either. On another post regarding dashboard rattles (I’ve read everything I could possibly find on this), someone described the sound as a “geiger counter”. That’s a pretty fitting description.

It started quietly about 2 months ago and has (I think) grown somewhat louder since then. No abrupt changes in car or driver to point to a sudden change as a source. The noise starts once the car hits 20-25 miles an hour. It seems to get a little louder as the speed increases. Once the speed drops below 20 mph, the noise cuts out completely. The sound seems to emanate from the center of the dash towards the back, i.e., by the firewall. It almost sounds like a coin has fallen in the defroster vents (I looked, nothing there, and you would expect the sound to depend on HVAC settings (fan, air exit), but it doesn’t).

Here is what I have discovered about the sound over the past two months of experimenting:

The following do *not* affect the sound in any way:

• HVAC controls (any fan, any discharge or temperature setting, fresh or recirc., AC compressor on or off)
• Stereo settings, windshield wipers on or off or washer fluid has no effect
• Rattle is present when car is hot or cold, i.e., always.
• Rattle is present when outside temperature is hot or cold. It starts immediately once the car hits 20-25 mph, regardless of prior driving time or temperature.
• Does not depend on gear, or whether accelerating or decelerating (noise always present). This would seem to rule out the broken pitching bracket that has had a TSB issued on it. The pitching bracket helps keep the tranny in place, so presumably the noise would be strongly dependent on acceleration/deceleration, but it’s not.
• Doesn’t depend on pitch: present when going uphill, flat, or downhill
• Noise not sensitive to hard turn left or right, or straight ahead (still present)
• Pushing on any and all dash/instrument/info panels does nothing to alter the sound. I’ve tried dozens of different pressure points all over the place, but none seem to affect the sound one bit.

In fact, I can’t seem to find anything at all that DOES seem to affect the sound in any way, which makes troubleshooting so vexing.

I am still planning to have my wife drive the car with me as passenger to try to further narrow down the source of the sound. I also have a small voice recorder that records in stereo in high fidelity, and thought of placing it at various places along the dash to refine down the source. Perhaps I’ll post an MP3 of the rattle if the forums allow it.

This rattle is driving me insane, and I’ve got to get it fixed, or I will have to check into an institution in the not-too-distant future. I don’t trust the dealer to get it right, so I am facing, potentially, a complete dashboard removal and all related components, which I am looking forward to about as much as a root canal. I do have the factory service manual for the car, FWIW. I figured I would bounce this off the SB9T.com group as a last-ditch effort to get some ideas before plunging into the inevitable.

Thus, I ask:

1. Does anyone have any suggestions as to the likely cause or source of the rattle, and
2. If I do have to start tearing into the dash, any recommendations? I was figuring on pulling the nav trim to start, then the instrument cluster, then the audio panel and driving with each removed to try to isolate/find the sound. If none of those work, then out comes the dash (ugghh!!)

Anyway, all thoughts and suggestions welcome. Thanks, by the way, for a great forum dedicated to the B9!

-Joe L.
Long Island, NY

[Magic Marker]

Well, that is one long diagnosis! Our 07 had an indash rattle, but only during cold weather. It drove me nuts, but never happened in warm weather. One day last winter it started up again and luckily we were in the vicinity of our local dealer. I drove right over, had the service manager jump in the car with me and took a ride. He heard it and made an appointment to get it fixed.

They ended up pulling the entire dash apart and installing silence tape. They also, somehow, reinstalled it firmer into place. Rattling gone. Of course all of this was done under warranty. If it wasn't I would never pay for the labor to do it.

[Oscar]

I thought our dash had a rattle too. I would press on it and nothing changed. I then noticed that the rattle was gone when it was raining out. Turned out to be my wiper blades rattling on the windshield somehow.

Lift you wiper arms off the windshield and take a drive to see if it helps.

[gandalf1]

Thank you both for the posts.

Funny, regarding the wiper thought.

Just a day or two after I posted my original message, it snowed in here in the Northeast. Then, with snow on the car and while driving...no rattle. Got me thinking.

Then today, another light, wet snow. So I did some more experiments. I cleaned the entire car of snow, except near the wiper landing area and associated cowl. No rattle. Then I cleaned the passenger side, but left the driver side packed with snow (the rattle seemed to be coming from the left (driver) side). No rattle.

Lastly I removed as much snow as I could from the driver-side wiper and area, and... a small rattle. Definitely seems to be (a) on the outside (thank goodness!!) and (b) located somewhere near the wiper or cowl area.

I will indeed lift (or remove) the wipers and give it another spin. Will report back with the results.

Thanks again!

[Tribeca_06]

open your engine hood and check in the vents in front of your windshield...may be leaves...thats what happenes to mine..it sounds like its from the dashboard like something is loose but its only leaves

[3Beca]

Have experienced same maddening rattle and cannot determine source ... comes and goes without rhyme or reason ... cannot control vibration or muted plastic on plastic "rapid" rattle by stopping/starting or "banging" on dashboard ... do not believe that it is caused by outside vibration of leaves/blades rather by something inside dashboard because the beat is too similar in each case (exact same sound in each case) ... nevertheless will try suggested remedies in hopes of not having to remove dashboard before going crazy.

[Tribeca_06]

see the dealer?

[Magic Marker]

Originally Posted by Tribeca_06

see the dealer?

Only if he's under warranty. I can't even imagine how much that would cost diagnose and fix outside of warranty.

[gandalf1]

Well the plot thickens. I pulled both wiper arm assemblies off but still had the rattle. Then, I thought I finally found it: the windshield washer jets attach to metal slots in the underside of the hood, but the fit is very loose, and they clearly are free to jostle around in the mounts. As a diagnostic, I used some masking tape over each jet to press it against the hood to arrest any movement and...rattle GONE! Drove the car for 2-3 days like this with no rattle.

At least so I thought. I could swear I heard it for about 1/4 mile over the weekend. (starting to hear things now?), and I pulled over and check the tape, and actually removing it from one jet (hoping that the rattle would come back in full force with the tape removed), but instead it fell silent again, and has been deadly quiet all of today. It may well still be the washer jets. I need to explore further. Another possible candidate is the cowl itself, which seems to have some play in it. At the very least, it appears to be located on the outside of the vehicle, based on the poking and playing around that I have done (and the snow diagnostic from an earlier post). I'll get to the bottom of this one way or another and will report the final culprit.


And regarding the dealer, yes, my thoughts exactly regarding the cost. The car is out of warranty, and unless they have come across this problem before, I don't have a lot of faith that they can do much better than I can. Given the lack of posts and discussions on Tribeca dashboard rattles (I've searched and searched), I woudl hazard to guess that it's not a common problem.

I've also lived with this freaking noise front and center now for going on 10-15 hours now, thinking about it, testing, exploring, and generally driving me insane every minute of the way. I also happen to be a research engineer as my profession, and a big part of the job is doing obscure troubleshooting on new systems that are still very much in the prototype stage. You get used to identifying obscure trends. To compound the problem the noise requires that the vehicle be in motion at a speed of at least 25 mph, which really complicates the troubleshooting process.

Not to say the dealer couldn't fix the problem quickly and easily, but, in my humble opinion, the odds are just as great that they will log 8-12 hours tearing into my dashboard, never to be qute right again, and only have the problem persist. For the time being I will, as they say, go it alone.

Incidentally, here's a couple of other things I was thinking to try (and may still do if the damn rattle comes back again). (1) take a small recorded and place with double sided tape on the dash and even in the the exterior cowl compartment to see if the sound can be isolated. The recorder is stereo (A Sony ICD-UX70), hence there is a chance (hope!) that the origin of the source can be determined left or right of the recorder because of the stereo mics.

Another thought is to make a CD that contains a slowly swept sine wave that goes from, say 10 Hz up to 5 kHz linearly over a time span of, say, 5 min, then pop this CD in the stereo, crank up the volume, and listen for the rattle when the frequency sweeps past the resonant frequency that sets it off in the first place. (After 10-15 miutes of this, though, you will need to be institutionalized, or drink large volumes of alcohol: it is maddening). If you are lucky enough cause the sound to appear (without driving), you could then make a second CD with just that frequency and then try to go around the car to find the source without driving the car. Haven't tried this yet, but I will if I can't get to to the bottom of this.

Thanks again for all the comments and feedback. To be continued...

[gandalf1]

Update: it's been over week now, and the rattle is definately gone. Wonderful thing.

What is disturbing, though, is that I never did definatively find the reason. I thiink that it was either (1) the windshield washer jets as described above, or (2) another possible source that I noticed when putting the windshield wiper arms back on: there is a plastic cowl that covers the base of the windshield on the outside of the car, and that both of the windshield wiper arm shafts pass through from below. Around each wiper shaft is a vertical plastic well that is an integrated part of the cowl itself. Interestingly, the base of this well rests on the windshield glass, and there is also a gap there. I noticed when putting the wiper arms back on that a couple of Maple ("helicoptor") tree seeds had fallen into the well, and the blade of the seed was wedged in the gap between the base of the well and the windshield glass. On a lark, I pushed the seeds further in to form a definative wedge before reinstalling the wiper arms. After doing this...no rattle. I suppose in a few months time the seeds will decay away, and if the rattle shows up I will look there. Also, I still have the passenger-side washer jet taped up. That will come off eventually.

Truth be told, though, despite my nagging curiosity, I'm afriad to meddle with this any further, for fear that the horrible rattle will return with a vengance. Thus, I will in the short turn, enjoy the peace and quiet. If it ever shows up iagain, and/or I do find the definative reason for it. I'll post a follow up.

Thanks to everyone who responded with thoughts and suggestions.

-Joe

[Scottw305]

I also have the annoying dash rattle, as well as the rear hatch rattle that the dealer can not seem to fix even though they performed the TSB. I'm going to have the dash rattle looked at as soon as possible, because it is driving my wife and I crazy. I will post the results. This vehicle has been an extreme disappointment.

[Tribeca_06]

is it a rattle in the dash or is it like a "click" when you hit bumps..i get that sometimes..

[njjuliano]

I had the rattle and at times I think it the leaves, as a previous poster mentioned. I have moved some out of the way, and had the noise disappear.

Other times, I have pushed on the dash from the inside thinking I have removed all possible leaves, and from pushing on the dash, the noise disappears. I'm assuming as well that the dash needs a bit of a wedge with the windshield to get a "tighter fit."

Obviously, mine are purely speculative. IF it comes back, I'm going to move those wiper arms wildly, get an ACME vacuum and get all the leaves and seeds from the vents, and then insert all the foam wedges I can from the inside.

That should do it.

[Scottw305]

Our dash rattle definitely stops when you put a significant amount of pressure on the back of the dash.

[LORE BECA]

I have noticed same and when applying forward pressure on dash the rattle stops so it has to be loose dash and not enough foam to stop rattler. How many miles do ypu have on vehicle?

Originally Posted by Scottw305

Our dash rattle definitely stops when you put a significant amount of pressure on the back of the dash.

[ghmolina]

I have the same problem, they changed a transmision mount in the center upper area of the tansmision it self, this mount was just a liitle bit of the problem, because after a deeeper inspection, we found that the noise comes from a cracked factory weld, which of course is not covered by any warranty. The only way to fix this crack, is taking out the engine and even the trasmision it self, and also consider to deal with future problem if the engine and transimision is unmounted & mounted back by non-Subaru people. So I guess that I'll fix it putting the radio volume up.

Good luck you all.