Belt Squeak / engine noise

Hi

My 2005 A3 TDI has started to develop a squeaking / chirping noise which appears to be originating from the belt on the drivers side of the engine.

At first I thought it was simply the belt slipping but it seems tight and there is very little play. Having looked under the bonnet when the engine is running I can see something (sorry I don't know what it is!) jumping about near the belt. The engine also seems to be struggling more than it used to.

I saw something on the internet saying to pour water on the belt to help diagnose and when I do this the noise stops for a short time, the engine seems to lower its revs and quietens, and the part which was jumping about seems to calm down. After a short time the issue returns, probably as the water dries up.

I have taken the following video which shows the issue




Can anyone help diagnose the issue and give me an idea of how to fix it?

Apologies for the vagueness. I am happy to give anything a go but please assume I know nothing about my car or the parts under the bonnet!

Info which may help

2005 2.0 TDI a3 DSG 8p model
The noise is intermittent (although becoming more often) and can be started and temporarily stopped by switching the econ button off. However the noise can also start even with the econ button on (a/c off).

Thanks for any help

Wayne

max69vk said:

Check the alternator pulley, give it a squirt of wd40 if required. The one way pulley on the alternator can get noisy when they get dust in them + extra load from using the AC can make the issue more prominent.

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Thanks

Where do I need to squirt the wd40? Down the side of the pulley (between it and the alternator) or where the bolt secures it? I have some copper lubricant spray. Would that be better?

NHN said:

Also just changing the belt gets rid of the noise, for sake of £12 or whatever it is now, I would swap this out as friend had same issue, swapped belt for him & problem gone.

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Still noisy after WD40 and copper grease. Are there any good guides available online for changing the belt?

NHN said:

As he says lol

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Brilliant. Thanks for the quick response.