A4 Droning noise - Help!

[Burt25]

Hi, this is my first post and I'm hoping someone can help. I have a 2001 A4 130 Sport which has developed a droning noise. I thought it wa the exhause, but I had it checked by my local dealer and they said it was fine; they suggested the air filter, which I changed but the noise is still there so I'm back to square one.
The noise sounds like its coming from the drivers side of the engine bay (around the air box / turbo pipes) does anyone have any ideas??

 

[technics100]

What revs is it droning at? My 130 seems to have exhaust drown at about 1800-2000rpm..is that the same as yours?

 

[Burt25]

Hi Technics100,

Yes the droan is around 2000rpm - Took it to Isaac Agnews who said there was nothing wrong with the exhaust. I thought it might be broken exhaust baffles? - They said the baffles are OK, but how can they be sure when they are inside the exhaust and cannot be examined?? When I open the bonnet, the noise seems to be around the engine bay - dont know where to go from here to get another opinion. Do you know of any good independant local garages with audi knowledge?

 

[Burt25]

Technics,

Do you have any idling problems? - My A4 also has developed a lumpy idle, dont know if this is connected with the droning - perhaps if some baffle material was blocking the exhaust?

 

[The911SC]

could be wheel bearings... Does it groan when you take it out of gear and coast?..

 

[Burt25]

Definatley not bearings - no noise when I'm coasting. I was just on the TDi Club forum and discovered that there is a common fault with B6 Passats where the flexible part of the exhaust stiffens over time due to build-up of exhaust particulates, causing a droning / resonance. I assume the A4's exhaust is exactly the same as the Passats? - So this could be where the problem is -Any one else coma across this??

 

[technics100]

Mines the same definately coming from the exhaust just started a few months ago, I have 105K on the clock, so thats maybe what it is. Any ideas on how to sort it out? does it mean new flexi pipe?

 

[Burt25]

Hi Technics,

See you're also an architect in Belfast! small world!
I rang agnews and the flexible part is part of the Cat - so £400 to replace!, However, you can buy an aftermarket flexible pipe, have the old one cut out and the new one welded in in its place. If you have a look on TDI Club, there are a few posts on this. Is the noise from yours loud enough to be intrusive? - I need to turn the radio up an extra notch as it really grates on me after a while.

I spoke to an independant mechanic who says he can cut the pipe out and replace it - just waiting for a cost for the part (assuming thats where the problem lies)

PS My car has 90K on the clock so not disimilar mileage to yours.

 

[VACINC]

townies, you belfast ones ?

 

[Just Plain Old]

Does this 'droning' noise emanate from the passenger seat...........? If so check there isn't a female sitting in it!! /ubbthreads/images/graemlins/smirk.gif

 

[imported_bubstar]

[ QUOTE ]
Does this 'droning' noise emanate from the passenger seat...........? If so check there isn't a female sitting in it!! /ubbthreads/images/graemlins/smirk.gif

[/ QUOTE ]


Nice one JPO!

BUB /ubbthreads/images/graemlins/laugh_roll.gif

 

[Burt25]

Anyone else any ideas?

 

[technics100]

I'm going to try removing the flexi-pipe and beat the SH*t out of it until it frees up a bit. Shouldn't be too bad to remove as its bolted to flanges at each end and is quite short.. The flexi part is the bit between 4 and 1. will let you know How I get on

 

[Burt25]

Hi Technics,
I will be interested to hear how you get on - I was going to replace the pipe, but my Mechanic reckons the problem is more likely to be loose exhaust baffles. Let me knoe if you make any improvment. By the way - Isn't the flexi pipe are of the CAT?