Another noise

[Rsnail]

Hi guys, over the last couple of days I started to hear a weird noise from somewhere under the car or from the engine bay, but can't say for sure as I can't figure out where it's coming from. Imagine hearing the sound of someone slowly dragging a brake disk on a concrete floor from the other room with the door shut (saying from the other room with the door shut because it's that type of sound I noticed, but a little damped). It's like a metal on metal type of sound, but it's only heard with the radio on mute and when closely listening, and only when driving the car and slowly accelerating it and slowly gaining speed, I can't hear it while slowly accelerating with the car parked. Anyone got any ideas? I checked all the brake pads and they're not worn at all.

Here's the link to the recording of the sound, it's better hearable towards the last third of the recording if closely listening:

Noise

[Blink]

It sounds like a brake backplate vibration to me. 14 secs onwards.

[Rsnail]

Yes exactly it can be better heard from 14 secs onwards, also thought about one of the brake backplates, will have them checked out as soon as I have the chance

[Rsnail]

Went under the car and found out that the noise comes from the exhaust, more precisely from the front side of the exhaust (near the engine), but the weird thing is that I swapped the catalytic converter some months ago with a brand new one, and to test if the cat is again on it's way out, I pushed a steel bar against it to stop it from vibrating, and the noise was still there when slightly accelerating, also, brake backplates are good and not rubbing against the disks, I spun each wheel in the air by jacking each side up and the wheels spin freely without any noise, no stones trapped, and also, the heatshields above the exhaust are all intact and not touching any part of the exhaust...

[Blink]

Maybe there's something inside the cat that's rattling - with and without the steel bar.

Are any of the heatshield bolt holes eaten through (they usually are), allowing the heatshield to rattle around?

It does sound like backplates, exhaust or heatshield - I can't think of anything else that would make that sort of rasping noise.

[T-Cut]

Originally Posted by Blink

Maybe there's something inside the cat that's rattling - with and without the steel bar.

The V6 models had a notorious tendency to suffer detached catalysts. The ceramic element was/is(?) attached to the outer case on supports that came adrift. This allowed the ceramic element to rattle as the speed increased. There are loads of threads in the archives. The 1.8Turbos also had their moments.




TC

[Rsnail]

Would this be possible with a brand new catalytic converter purchased 3 months ago?

[75driver]

What condition are the rear arms like?
When mine were on the way out, i had metallic rubbing noises, but only going round corners or over bumps.
Not that similar to your problem, but worth a check.
I could see where the inside of the tyre had been rubbing (on the trailing arm I think), but obviously only happened with the weight on the car.
With the weight off the car,there was a reasonable clearance between tyre and trailing arm.


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[Rogue]

I could see where the inside of the tyre had been rubbing (on the trailing arm I think)

If that was the case it should be fairly obvious and look a little like the below.

[Rsnail]

Rear suspension arms are also relatively new (1 year old), bought as new