Noise from rear trunk
 

I don't know if this is a problem or not. My 02 Boxster S is running great. Just passed it's annual mot with no faults found. However there is an annoying noise coming from behind drivers side (right) when I go over bumps or potholes in the road. I have to add that the roads here in the UK are at an all time low for pot holes. It's hard to describe, sounds like something is thumping about in the trunk, like a loose floorboard. I lifted up the carpet in the trunk and underneath there is a sheet of hard foam which is jigsawed together to form a hard surface under the carpet. If I tap this it's kind of loose and I wondered if this was the source.
I know from experience that a liitle vibration can be amplified by the body of the car. We have a VW Golf that also had a really annoying droning sound that appeared when the engine was labouring. This turned out to be two screws that hadn't been tightened around a filter casing near the radiator. Once tightened up the noise was gone.
There no continual noise, just over bumps and it's not there all the time. I also can't hear it when the soft top is down.

Anyone got any ideas?

Could be the control arms. Check all 3 to see if there is any play or movement. Those get very noisy over time. I've changed all 3 on my left rear side and it doesn't make any sounds. I'm waiting a couple of months to move on to do the right side. It makes a big difference on how the car drives.

I had a rummage under the exhaust on the right hand side and found one of the clamps had corroded and was loose and spinning around pipe. It was so rusted I could prize open the clamp and remove it. I found the one at the left was pretty much the same, but this one wasn't loose and moving about. Again I was able to prize it apart and pull it away from exhaust pipe. This is at the point both pipes join the silencer (muffler). The pipes appear to have welded in place so they're not moving, but I will try to find replacement clamps anyway.
Can anyone suggest replacements? Would jubilee clips do the job?
Not convineced this is source of noise. It did seem a lot quieter going over bumps but will see over next few days.
I might have to give up and get the garage to check control arms, bushes etc, but trying to eliminate simple cause before I do that. I've seen other posts where exhaust/heat shields and other loose components can give annoying noises.

Oh joy!

Sorry Rui725 controls arms appear to be ok, but could you give an idiots guide to how I should check them. Does the wheel need to be off the ground?

Another thought is the front motor mount. Once it fails, the motor can move around a bit and transmit all kinds of weird sounds into the cabin that sound just like a rear suspension issue.

I know this from experience after spending hours and hours looking at the rear suspenion and having a shop do the same only to find it was the motor mount.

Just an idea for something else to check if the rear suspension looks ok.

Once it cooled down I found that the left hand pipe is still solid whereas the right hand pipe I can move, it's loose. So I now have both clamps removed. Remember the one on the right was rattling about. I wonder if removing both clamps has improved things ie no loose clamps but because the pipe is loose I'm still getting some noise.
What sounds like a ding outside the car can sound like a dong inside the cab!

Sorry just thinking out loud.
Need to get some clamps

Hi, eventually took car to workshop and mechanic came for a drive. He recognised the noise right away and put it up on a lift to show me where the problem is. It's part nmber 8 identified in the diagram. Part ordered booked in for next week. Will update asap

My guess was a Druid in the rear boot!

Noise gone, invoice says replaced trailing arm. I asked mechanic to replace reverse light switch while they were working on car. Reversing lights were sticking on. parts plus two hours labour total was arround 430 pounds or $700.

Trainling arm alone was about 240 pounds $385.

Alan

This has to be the same problem that I am having. Brought it in for repair with 120,000 servicing and they did not find cause, of course probably did not look very hard.
Thank you for sharing this news. Will have trailing arm checked..

I had similar noise I think. It was perfectly described on one forum (which I can't remember) as the sound of pool balls being emptied from a pool table. If it does turn out to be the part you identified then you may have to budget for all the other one on the other side and the similar front two. I assume they have similar service lives as my other side started making a noise a couple of weeks after the first. A month later I got a similar noise from the NSF and now I have the OSF on order! I happened to notice today there is an article in '911 and Porsche' magazine about replacing the bushes with poly ones. I didn't read it all as I just flicked through it on book stand but maybe this is a better/cheaper solution than replacing the whole arms with Porsche OE.