Preeble

I have a low-pitched rattle (or series of clunks) on my 2008 CS that occurs when I'm driving slowly (<25mph) and going over rough roads. I suspect that it also occurs when I'm driving faster, but it is less audible and resolves itself faster.

It sounds like it is coming from the rear suspension or hatch, but I cannot pinpoint the source and ideally would like to either fix it myself or tell the dealer exactly what is rattling when I take it in.

This noise is not from the luggage cover as it is out of the car and I have ensured that my rear seats are completely locked into place. I have done preliminary checks around the hatch area and it seems that both the window and the door close tightly. The only thing that is visible that could rattle is the metal flap that covers the metal loop that the hatch closes onto, but it seems doubtful that this flap could be causing that noise...

This noise cannot be normal in this car. Any thoughts?

Renn 951

The seats can still rattle even when locked in place; they still move a little as the vehicle flexes. I tuck a little soft foam packing material between the seat back and the vehicle sides (right underneath the locking pins) and no more noises!

Preeble

Good advice! I will look into that.

k722070

please post again if it turns out not to be the seats or hatch.
I have the clunk(or series of clunks) sound in my 08 gts only at low speed while turning over a bump, like into a driveway.
dealer will admit that the sound exists but their inspection turns up nothing so they say it is normal.
I would find it interesting to hear what your dealer says.

Preeble

Will do. While I hope it is the seats and I can fix it, I fear that it will not be. To me, it really sounds like a vibration in the suspension...

medtech

Is the license plate secure?

Check the cargo boxes and the spare tire area as well.

Preeble

It is - I even took off the dealer's bracket in an attempt to eliminate noise.

I looked in the cargo area and it appears that everything is locked down, but I will look again. Perhaps I missed something in the box area...

f4 plt

If you have a towing package, is the draw bar installed? There is some play between the draw bar and the sleeve on the tow hitch that it slides into and this can cause a random rattle or thumping sound as you drive slowly over bumpy roads. Also have you checked for anything loose in the spare tire storage compartment?

Preeble

My commute to the office is especially bumpy so I just tried a few things, but still no luck identifying the cause.

I have confirmed it is not the rear seat latches as I drove with the seats down. I also don't have anything in the hitch receiver so that is not the source of the noise either (although I suspect that noise would be very similar to what I'm hearing).

I looked in the spare tire compartment and everything appears to be buttoned down well. My next step will be to take everything out of that compartment to see if there is a difference.

I'm also starting to question the source of the noise - perhaps it is coming from the front... it really does sound like the rattle is coming from the suspension because the rattle/clunk noise is in tune with the wheels 'hopping' over the bumps. I took a quick look in the wheel wells to see if I could see anything, but there didn't appear to be anything that could be the source of the noise.

Still searching...

medtech

next step is to buy a cheap double barrel stethoscope and have someone else drive while u hunt.

or, you could just turn up the radio...

Preeble

Someone in my car today mentioned to me that it could be noise coming from the mounts/bushings coming from the transfer case. Could this be a possibility?

HD2pct

Noises are probably the hardest things to troubleshoot. But based on everything you have described, it is highly doubtful that it has something to do with the, uh, "transfer case" mounts.

Have you opened up the floor cover in the hatch area and maybe suspended it on a blanket to see if it's the cover or perhaps something underneath it?

The idea about the seats was a good one too. That usually manifests itself in sort of a "squeaky" sound versus a rattle.

Preeble

I searched through the Cayenne TSBs and came across this one - "Rattling Noise In The Area Of The Steering Shaft and Driver's Footwell":

Rattling noise may occur in the vicinity of the steering shaft and the driver's footwell when driving the models Cayenne (V6), Cayenne S and Cayenne Turbo over an uneven road surface (e.g. cobblestones) within the speed range of between 18 - 24 mph (30 - 40 km/h). The reason for this is the play between the steering shaft and the steering shaft bearing on the upper universal joint.

This TSB is from 2004 - what are the odds that a 2008 car would still have this problem?

Up next - I'm going to take my stethoscope and listen to the steering shaft ;o)

Preeble

OK - so after driving around some 'cobblestone' today, it does appear that this rattle is coming from just in front/under my feet. I'm going to give the dealer a call next week...

Preeble

Update... I took the car to the dealer and he thought that the noise came from the rear springs. They replaced the springs under warranty and no more suspension rattle!