Have an odd problem that only occurs when I have passengers in the backseat.
Then there is some kind of noise that is hard to explain. Kind of low frequency and doesn't follow the valve. It's not the exhaust system, that far i know. Understand it might be impossible to even have a guess, but maybe someone have their own experience of a similar problem and maybe some ideas to share. Thanks!

What is the sound??
I didn't understand you, sorry for that..

Does it get louder if you go round a corner one way and quieter the other? a low whirring noise that's louder one way and not the other is likely to be wheel bearings.

Also, check the tires, one of mine was warped a while back and caused noise and vibration just like rear bearings failing but wasn't direction related.

Either that or you just have nervous passengers making funny noises

Ha ha passengers in my car make high frequenced sound
No it's the same sound even in corners, no more or less.

A low frequenced clunk is the only way I can describe it. And that from listening while driving with all other noises going on. It's not a rythmic sound following the valve or something. Can't even say it sound more even on a bumpy road or maybe I just don't hear it for other reasons then.

Not to freak you out but if you have rust under the car it may be the rear top munts,rear spring snapped, rear strut mounting points rusted..
You have to inspect it fast to be sure that this is not the case, or you could be dangerous to you and other people.

Also i got in mind wheel center caps as mine (on the 14" wheels) are mooving and make a good 1year searching sound till i found it just by accident washing the car..

It could be something like that..^^
Hoping it's something like that..

Okay. You mean the mounting up in the towers? That rubber "thing" that is on the top?
Whats strange is that it should make noise even without passenger back if that would be the case. The cars weight itself should be enough to make that sound appear if it was that bad I think. But I might be wrong.

From what I can see the towers look fine, no rust on the mounting points. It hasn't either sunk down and become "jumpy" in the back.

Had it in for our yearly security inspection in April and the only thing they found was a weared out steering joint which has nothing to do with this problem. But sure they could have missed something.

Same with the wheel cap, it should make noise even without passenger back if that should be the source of the sound.

From my point of view, something happening when the weight is higher in the back, a higher pressure and different position of the rear part create something that makes that sound appear.
It's enough with 80-100 kg.

Thanks for your thoughts Have a good day!

does the noise change with speed or is it a now n then muffled clunk?

Now and then muffled clunk. Only with passenger back, never when I am alone in the car.

Hi ghoststrokes, some suggestions:

If it's related to a person in the rear seat see if you can replicate the noise doing the following:
1) Try someone in each position, see if you can isolate it to one position.
2) Try a comparable load in the boot instead of a person on the back seat.
2a) Try a comparable load in the rear seat footwell instead of the seat.

This may help locate/isolate the issue to a particular area. What I'm aiming at (and you can quickly check anyway) is an issue related to the passenger cabin such as seat/seat back mounts, seat belts/seat belt mounts, seat back latches.

Something other relatively simple things that could be checked are e.g. a loose or misrouted hose (brake) or cable (handbrake) that is moved closer to the chassis/suspension component by the weight of a passenger in the vehicle or a cornering force.

A loose bush or perhaps worn drop-link could also be the issue.

Patrick

I had a knocking one from the exhaust hitting the right tow hook.. intermitment..
I have rubber on the hook now and i didn't hear it.(i didn't noticed it anymore)
See if there is something wrong with the back box rubber hangers and if it plays alot, this could be it.

Hello Patrick!
Thanks for the ideas!
In general it's hard to locate sources of sound from inside the car but I think it's from the rear left side. Have to check the drop links. Is that another name for what we called stabilisator joint in Sweden? A lose bush? Is that related to the rubber holders for the exhaust system? If so, they are fine and the system is not loose, actually it's almost rock steady. Need an english/ swedish dictionary for car details it seems. . Thanks a lot Patrick

From my experience with the 2l ba (I believe it has uprated suspension) I use the car as a daily so every week when I go shopping the back sags a lot from as little as 6l of milk.
I've had some intermittent knocks in the back myself.
From the front i think i need to check my cv joints as they always protest while pulling away or turning. I've had failed links before in the front and they don't sound like that plus they are solid.
The exhaust seems new on mine. I need to do a full inspection at the rear at some point. I think mine is right side of the car

open back door, stand on door sill and bounce the car as hard as you can. if its suspension or exhaust related you should hear it clunk but louder and clearer. do both sides to be sure.

Thanks I will do that! Probably my own joints will sound more with that exercise

Yes, better than my suggestions!

Also you'd pretty much got the translations right ghoststrokes:

"drop links" mean stabiliser (roll) bar links- they join the stabiliser bar to whatever it attaches to (e.g. strut, control arm, etc)

You're right with the "bush" assumption. I suppose a "bush" could be described as "something solid enclosed between something else that permits movement at a joint". So, for example, the rubber bushes join the suspension parts to the chassis/subframes. But you can have rigid bushes too, e.g. phosphor-bronze sleeves, nylon sleeves, etc that allow shafts to turn (sleeve bearing). They can also be used to absorb vibration and seal a joint. It's a fairly generic/colloquial term.

Patrick

Perfect explanation Patrick!
Great job with that!

Links or joints and bushes ("bushes" kind of makes me do other associations as well )
Is parts that our yearly carcontrol inspect carefully so they are not weared out. But of course things can broke after inspection.

I have had this sound for a long time and my guess is that it might be missed by the inspection because they do it on a empty car with no weight pressure of the back.

Another reason that I thought of and that have been mentioned is the bush (rubber part I guess) up in the towers where the struts are attached. They work like stoppers and anti-vibration I assume, so it's not attached metal against metal.

But it takes a closer examination with the parts disjoined to see the condition. The towers itself looks fine.
Thanks Patrick!

I did the "jumping test" yesterday quickly and I did hear some noise from both sides. Couldn't check it out deeper as my kids was with me.
It didn't sound like the exhaustsystem, more the suspension. Need to have some assistance that could look closer while I do my athletic jumping.

ok, did the car steady itself quickly when you finished jumping? if so the shockers(dampers) are fine. Most likely the the drop links as patrick says. Using a small bar try and lever each end, worn ball joints will part or slip out. Not too much force as even new ones will part with enough force. If you do part one with little force just knock it back on with some grease and hammer until you can get it replaced.

Yes it gets steady direct. Is it common that the droplinks worns out quickly on this cars? And, just to be sure we talk about the same thing.
This is what you talking about?
Although, I have had this Links (The picture) replaced 3 years ago and I never heard a sound like the one I have now when the old ones were worned out. That's what confusing me. One in the front was broken when they controlled the car but that gave just a rattle sound in corners.

There is also the possibility of the suspension bushes being worn and allowing the arm to knock slightly. Those bushes would still prevent most noise but they could allow a bit more travel causing knocks at certain angles and forces. Links are rather common though. Check the rubbers on them and if they look really old just replace both of them, they are fairly cheap in the UK.
When my front ones gave way last time they separated completely

As nafre says:

1) The links can be a common issue.
2) Bushes also- wear or perhaps shrink with age. The gap created then causes a knocking noise. Can often sound like a soft, irregular dull rattle or knock (klock-klock-klock).

Patrick

Talking about bush. This is what i've been thinking of. Up in the towers where you attach the strut. Like hell as a swedish guy to explain something that I hardly can explain in my own language. Sorry for that. Trying my best.
Here is a pic of the part I assume your meaning can be worned out and causing a gap..

But I still think a gap would make noise even without passengers back. It's totally silent without passenger. That's the weird part in my opinion.

those are strut mounts. you can see them from inside the boot. just remove the plastic liner. I had one of these go on me and its not a knocking, the rear end starts to drift steer. check them anyway just to be sure

Okay I understand. According to the language problem maybe someone can have the kindness to attach some pictures of the bush, drop links and whatever your suggestion is that might be causing the sound. Hard to really find translations on specific car parts that doesn't confuse you even more. Thanks a lot for your suggestions!

Perhaps also check the seat belt/seat belt mounts/ seat belt inertia reels. I suppose you could plug the seat belts in with no pax and see if the noise recurs. Also perhaps check the rear parcel shelf is clipped in properly and nothing's loose in under the carpet in the boot, e.g. in the spare wheel well.

Just trying to concentrate on the "or?" part

Patrick

Got ya! I will check that!
Thanks!

I would check the struts and springs also.