Vibration noise

widdy

widdy

Member
This is a bit difficult to explain, unless anyone else has had the same issue.

During the hot weather recently and driving with the windows down, I noticed a type of vibration/resonance noise when I would ease off the accelerator. It seems to exaggerate when passing by hedges etc. I think it can also happen when accelerating as well. (I will have to verfiy that)

Would it be the shield surrounding the exhaust or something else.??

I am not too worried yet !!

Thanks in advance
 
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This I think is just a characteristic of the car. I find that it is greatly reduced by opening the rear windows about 2 inches.Ive got used to it after 286k miles.
 
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No its not the infamous window noise, I know all about that one.

The noise ONLY occurs when I take my foot of the accelerator.

I don't hear it with the windows up and the radio on.

I will have to try and look underneath just to check all is attached.
 
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No I don't think so, it is more like a bird whittering but not high pitched noise.

I said it was difficult to explain.

I will try and listen again over the weekend if the rain holds off long enough.
 
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Spike

Thanks, checked the thread and it is definitely not the stone between the disc scenario, as I had this during the first round of A2 ownership and know exactly what that sounds like.

I am sure it is not "mooing" as it only seems to occur when lifting off accelerator.

I will be out in it tomorrow, so I will ask my wife to hang out the window and see what she can hear. I could try and get a copy of the sound via her mobile phone if possible.

I will update ASAP.
 
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Well been out today and tried various ways to re-create the sound.

Found it also made the noise when in 4th gear accelerating up hill from about 35 mph.

Also seemed to do it when just coasting along with feet completely off all pedals.

It certainly sounds a metallically sound as though something is vibrating against something else.

If it stays dry tomorrow I will have a look underneath and see what I can see.
 
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hello widdy i think I'm right in saying tdi a2's don't have a cat as such but a particulate filter---could it be that broken inside? as i have had 2 cars that the cats have developed a "rattle" at certain rpm/speed/load situations.
i can confirm it is really annoying so lets hope you get it sorted soon. all the best sumo
 
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yes i think it is on the first piece of pipe you see coming out from underneith the engine bay --looks like a small exhaust box. just a thought do the tdi have a heat sheild on the exhaust manifold or on the turbo as it could be that rattling?
 
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That was my initial thinking that the heat shield is rattling against something.

I might be removng the bonnet tomorrow, weather permitting, so will check then as also need to check off side headlight as some condensation is appearing in there. The headlight does not appear to secure enough compared to the nearside unit. I can press the headlamp and it moves slightly, whereas the nearside one doesn't.

Cheers
 
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Just found this on the Audi Website

Only if the car is used for any length of time at low loads, for instance in urban traffic, is the temperature of the exhaust gas actively raised to around 600 degrees every 1,000 to 1,200 kilometres, to prompt additional regeneration of the filter. The particulates captured in the filter burn off at this temperature.

The previous owner to me only used the car for short distances, ie weekly shop to Tesco, whereas i am now using the car every day, although not covering a great mileage.

So now that I am using the car more often, do you think that there has been a build up and needs a good clear out, shall we say ???

It will be getting a good long run at the beginnning of August when we go off to Cornwall for our Summer hols. Climbing those cornish hills and roads will certainly give it a good workout
 
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Hi Widdy
Not 100% sure but I don't think any A2 diesel models are fitted with regenerative diesel particulate filters. The long run in August will still do some good though if the car has been used mainly for short journeys. It would also be an ideal time to start using a fuel additive to clean any deposits from the injectors etc.

Cheers Spike
 
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Well got the bonnet off yesterday and found a few things.

Hopefully cured the condensation issue of the Headlight = rear cover not properly installed, end clips not seated correctly.

Water drain hose from windscreen not secured to other down pipe via tie clip.

Started engine and revved and few times to different speeds and released, but no sound ocurred. Also looked underneath, without jacking up, and no seeable issues.

Will have to see if occurs again.
 
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