What is causing a rattling noise from my car's rear when going over bumps
 

I have a 2005 Mazda 3 Sedan 2.0L with just over 200,000 kms and I took it to a shop and they said it was the rear struts. Well, I had them replaced along with the sway bar linkage and I still have the problem. Go figure !

The rattling occurs even when going over small bumps - sounds metallic.

Any ideas ?

Thanks.

Can you reproduce it by bouncing on the rear of the car? that's easier than strapping a friend underneath to listen :)
There are many heat shields and such back there, along with plastic stuff for the bumper and other covers. It also could be inside the car, like something fell into the jack storage location or spare tire well. You may be able to pin it down with someone else driving, then sit in the back, put one seat down to listen in the trunk - that can go a long way to finding the location of the rattle.

I can't reproduce the sound - it comes and goes. I'll have a look in the spare tire well. Thanks for the tips.

Did they replace the bump stops too? There is a plastic "tube" that shields the strut upper part and it fits in the bump stop, if the bump stop is worn out the "tube"is gonna sit on the strut and every time you rear bounces it produces a rattling noise like it was some metal...got mine replaced and bye bye rattle hope it helps

They said the bump stops were in good condition. I've had two different mechanics put the car on their hoists and both could not find any problems !

Still a mystery.

is it a light or heavy sound? can you describe it any better - like a single pothole makes it rattle or tick once? have you heard exhaust shields rattle before?

You may be able to ride in the back with someone else driving to listen where it's coming from.

I too have noticed some weird sound coming from the back pillars of my 2008 Mazda 3 Hatch 2.3L GT.

I had a feeling at first I might be hearing the sound from the tire changing equipment/spare tire (but a quick look seemed like everything was fine)

I might try to remove all that stuff and then drive around... only issue is that the sound is not constant, it only occurs, like mentioned, every once in a while. And from what I remember it was usually going over some sort of bump.

To me the sound sounded like something loose, possible metal on metal, being rattled into another metal.

Still trying to figure it out... haven't taken it to any shops yet.

Keep me posted if anything is discovered and I will do the same

Just an update,

This occurrence happened to me again, while I was driving about 60 km/h I was travelling down - hill and road crack (shitty roads here) caused my vehicle to buckle the suspension slightly. This buckle and compression of the suspension seems to trigger a sound that sounds almost like my tires are shooting up rocks into either the wheel well (and they are bouncing around = which I don't think would be capable of producing this noise) or they are making the sound of rocks inside the rear pillar (which could be more likely the sound and where it is coming from... but I don't understand how stuff could have gotten there).

I haven't had a chance to drive with two people (one in the rear listening) and since this isn't consitently occuring during bumps and cracks in the road... it can tend to be very frustrating trying to decipher...

If anyone else has discovered something, please let us know!

I don't actually have one of these (yet?) but I'm a tech at a dealership (not mazda) and we had one traded in over the weekend and I liked how it looked and did the oil change / inspection on it today and drove it home, I really like it. Got online here to poke around and see what was what... I'll see if the financing numbers line up on it tomorrow.

Anyway, one thing I noticed was there was a slight bit of play in one of the rear sway bar links.. these have a ball-joint type socket connection on the end where they attach to the sway bar. To check these usually (and in the case of the car I looked at) you can grab the sway bar and push/pull it up and down and feel and hear the play in the joint. It doesn't take much to make a racket. On the car I'm considering, the one with play was the left side... now this is also checked with the vehicle in the air on the lift, suspension at full droop. I'd suspect that so long as it's on level ground you should be able to shimmy under there and check it on the ground too, since there shouldn't be any load on the sway bar. This was a 2006 with 113k on it.

I have this problem too. I'm hoping its something internal, I'm going to test drive with someone looking for the source sometime soon.

Brake pads.

Had the same issue. If you want to give it a test,go over the same bump that made the noise, only holding the e-brake enough to put pressure on the pads... I ended up putting little pieces of aluminumbetween the bridge and pad. Good luck!

solution
 

I finally found out it was my rear brake pads. They were missing anti-rattle springs - small pieces of metal on the pads !! What an ordeal. Got new pads - everything is fine and dandy.

See attached image - left pad is good - right pad is missing those springs...

i have the same issue and going to get my dad to check in the am... it started after i hit a pot hole and where i live its almost impossible not to hit pot holes... fingers crossed that this is the problem

another solution
 

I had the same problem. There was a rattling noise coming from the rear passenger tire. I finally found it was the coil spring. About four inches of the coil spring had snapped off the end of it and was laying inside the lower spring seat. Every bump, large or small, would create a jingling noise as the piece bounced around. Hope this helps somebody. I was about to drive off a cliff hearing that noise everyday. :cool:

the same thing happened to my 04 mazda 3!!rattle was so loud i had to keep the windows up when on a bumpy road..got under car with a hammer and tapped sway bar links .heard the rattle but found it was coming from bottom coil spring seat.the bottom five inches or so of spring had broken off and was rattling loudly over road bumps.now i don't have to hide my face when driving in town over bumps!!so happy!