Noise when idling

Troender

Troender

Member
I just bought a 2002 A2 1.4 petrol, which has only been driven 98,000 km. The car is very well taken care of, and has been at an authorized Audi workshop for all services.

Everything works on the car, and it drives extremely well.

But there is a slight disturbing sound when the car is idling. It is difficult to hear on the outside, or in the engine compartment. But sounds better from inside the car. It appears to be coming from the transmission line / the firewall.

Here is a video of the sound. Does anyone have an idea what it might be?

 
It almost sounds like it's only firing on three cylinders. Could it be down on compression in one cylinder but still firing, and something like a worn dogbone or one of the other engine mountings is amplifying the vibration in the cabin? This would be less noticeable with increased revs.
 
Pressing in the clutch does not change the strange noise. It seems like the sound only appears when the engine idles below 1000 RPMs.

Transmission bearing sounds expensive.
 
Proghound said:
It almost sounds like it's only firing on three cylinders. Could it be down on compression in one cylinder but still firing, and something like a worn dogbone or one of the other engine mountings is amplifying the vibration in the cabin? This would be less noticeable with increased revs.
Click to expand...
The Car runs and accelerates as it should. And the motor sounds nice. No problems there.
And the noise is just audible from the inside.

So its not a misfire problem.

I have to add that the microphone of my iPhone actually amplifies the noise some. In real it is not that prominent.
 
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Sounds like something hitting the bulkhead area. Bonnet locators can rattle. Could be exhaust on the floor?
 
Proghound said:
It almost sounds like it's only firing on three cylinders. Could it be down on compression in one cylinder but still firing, and something like a worn dogbone or one of the other engine mountings is amplifying the vibration in the cabin? This would be less noticeable with increased revs.
Click to expand...

Yes it sounds a lot like when my car had a misfire and shut cyl. 1 down. Doesn't make sense that it's only audible inside though.
 
Troender said:
I just bought a 2002 A2 1.4 petrol, which has only been driven 98,000 km. The car is very well taken care of, and has been at an authorized Audi workshop for all services.

Everything works on the car, and it drives extremely well.

But there is a slight disturbing sound when the car is idling. It is difficult to hear on the outside, or in the engine compartment. But sounds better from inside the car. It appears to be coming from the transmission line / the firewall.

Here is a video of the sound. Does anyone have an idea what it might be?

Click to expand...
Hi Troender,
It sounds like relay chattering to me , I would open up the passenger front footwell & see if the noise is worse.
Dog bone mount loose or worn allows the engine to swing front to back excessively & is a quick fix.
Have you had any exhaust work carried out recently?
Hope that helps you
Keith
 
kp 115 said:
Hi Troender,
It sounds like relay chattering to me , I would open up the passenger front footwell & see if the noise is worse.
Dog bone mount loose or worn allows the engine to swing front to back excessively & is a quick fix.
Have you had any exhaust work carried out recently?
Hope that helps you
Keith
Click to expand...
I also think this is a problem that is related to the engine and / or gearbox vibrating against a body part. The reason for this is that the noise sounds very good in the cabin, but that it is difficult to hear anything from the outside.

So that it is a question of a worn, or loose engine or gearbox attachment is my best guess.
 
With the engine turned off, the bonnet off and you sitting in the driver's seat again, get someone to vigorously shake the engine back and forth and just general wiggling.

If required, jack the car up, remove the undertray if fitted and repeat.

Also, with someone rocking the engine you may just be able to see what's hitting what.

Relay: I can't see it myself, the noise is just too engine-speed related.

Good luck and be sure to report back 👍🙂
 
I would wage a large amount of money its the exhaust hitting the subframe or the underside of the body. The lambda sensor can also hit the inside of the transmission tunnel making a similar noise. Either way, defo exhaust related.

Ian
 
I had loose dog bone once (after steering rack change) and the sound of it clunking was nore when the engine got into power or when I got off the throttle. So it is not that highly possible but still possible.

As someone said - bring omeone other and rock the engine (when not running) and listen if the noise appears or not.
 
Hi All, New Audi A2 owner here.

The car I have bought has this exact noise. The noise can be initiated by moving the gearstick side to side or downwards on the gear stick.

Rocking the engine can replicate the noise, so my initial thought was dog bone mount (as noted above). However further investigation has identified the cause of the noise.

The gearbox cable where it enters the body is loose within the sleeve. As a result when the cable is under load or when engine is moving and vibrating it creates the rattle. I can replicate the noise by moving the cable.

Will look into whether the sleeve can be removed to try and fix the issue, there may be a loose grommet or broken clip. Will feedback if this helps.

Any advice on how to remove or inspect the cables would be appreciated.

@Troender did you find a fix for your noise?! Know first hand how annoying it is!
 
I have been working my ass of the last few weeks. So I have been living with the noise.
I was planning to do an appointment with my favorite Garage to test the motor/transmisjon mounts and dogbone.
But reading your experience tells me that we have the exact same problem. And your explanation sounds plausable.
I will be thrilled if this is the problem, because it sounds possible to fix this without emptying my pocets.

I have to read up on the gear cable.
 
@Troender hopefully this is the cause, I'm pretty certain as it can be replicated.

Have had a look at the diagram https://workshop-manuals.com/audi/a...elector_cables_exploded_view/#google_vignette and discussed with the person I looked at the issue with. They think that the clips (6) could be missing which would be logical as it would allow the clips to rattle within the housing.

Will check if the clips are available as a separate part.

Let me know how you get on! If you find anything different. Like you was also fearing the worst for this noise!
 
So this is like a bracket, or gasket holding the cable in place, going through the firewall? Right?
It makes sense, cause the sound is amplified through the body of the car at just that point.
 
My mechanic took a look at it today. The noise is definately comming from The cables all right. He tried a MacGyver fix fitting a smal rubber gasket between The cable and a holder/bracket. (See picture.) It made The problem allmost go away. He wanted to find some thicker rubber and try that next.
 

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I still have the problem. But Im probably about to replace my clutch. The gear box have to come out for that, and then it will be easyer to fix the problem.

I will keep you posted.
 
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