Help Please Strange noise.....HELP......

[Robarch2017]

Hi everyone just a quick question. I’ve just bought a Audi A4 b8 and I’m wondering what this noise is. It’s at just above idle when cars parked maybe 850/900rpm I took the video in my drivers foot well that’s where it seams to be loudest





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[Retroman]

What mileage? What engine? Decent service history? Does the knocking noise get worse as you rev up to say 3,000 rpm?

 

[Robarch2017]

Also I will add the noise isn’t there on startup only after a little drive round the block then if I just tap the accelerator it’s there


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[Robarch2017]

Hi retroman thanks for the reply.
It’s got 146000 on it full service history it doesn’t get worse it always sounds the same. It’s almost like something’s rattling from the dash or something in the middle of the car.
I’ve checked the airbox took it out and re installed it checked all plastic trims in the engine bay. And to be honest when I pop the bonnet I can’t hear it at all. I’ve tried leaving the ac on to see if it’s the tensioner for that. Just at a bit of a loose end without tearing the whole thing apart was just hopping someone else had a similar issue.


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[Robarch2017]

I’ve read in a few places it could be the carbon solenoid valve or loose exhaust bracket hitting the steering column I will check both of these on tues


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[Retroman]

Whenever people talk about "knocking" on a warmed-up engine (and we have limited info on a forum) ones mind always goes to something like "big end" bearing failure. However, this would tend to get louder as the engine is revved. If yours is the same regardless of engine revs then it may well be something linked to engine vibration and not RPM. As you suggest all you can do is inspect things like engine/gearbox mounts and exhaust mounts. Generally speaking exhaust mounts close to the engine tend to be 100% metal and can rust away causing vibration and tapping against other components.

 

[666markyboy]

What happens if you press the clutch ?? does the noise remain ??

 

[desertstorm]

I would say it's the DMF, As the post above asks does it change if you press the clutch maintaining the same RPM on the engine.
At that mileage over 5 times round the planet possibly due a new clutch anyway.
This is what they sound like when they are really bad.

Yours is probably just starting to go. Possibly why it was sold on. Did you get it from an auction/ garage ?.

 

[Robarch2017]

Well sorted. It was the dpf bolted up at a funny angle hitting the heat shielding where it connects to the flexi so simple.

But I will say I have on the list for the new year is a new belts and new clutch. Dpf removal and remap



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[Robarch2017]

I would say it's the DMF, As the post above asks does it change if you press the clutch maintaining the same RPM on the engine.
At that mileage over 5 times round the planet possibly due a new clutch anyway.
This is what they sound like when they are really bad.

Yours is probably just starting to go. Possibly why it was sold on. Did you get it from an auction/ garage ?.

Thanks for the info I know what to look for now if mine goes lol


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[desertstorm]

Glad you found a cheaper easier fix. Always difficult trying to diagnose what does this sound like videos or sound files. If the noise stays the same pressing and releasing the clutch it's likely not to be a DMF.

 

[Robarch2017]

Glad you found a cheaper easier fix. Always difficult trying to diagnose what does this sound like videos or sound files. If the noise stays the same pressing and releasing the clutch it's likely not to be a DMF.

Yea that’s what my mate said so we got it up on the ramps and there it was rubbing


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[Jbradford97]

Be careful with the DPF removal.
Following Diesel gate, the Government are looking to testing exhaust gasses as part of the MOT, rather than just the visual check they currently.