Funny noise under acceleration

[PenguinGTI]

Hi guys, looking for some advice about the car:

I've put this in the mk6 section and in here as I don't really expect many mk6 owners will have done similar mileage to myself
The problem

Some times when I am accelerating the car makes a funny sound. I don't quite know the word to describe it but it's almost like a squeak. It occurs only when I throttle.To narrow it down I've been keeping my foot on the throttle at various revs and the noise occurs just before the whistle of the turbo spooling.

At first I thought it was maybe the throttle but I can accelerate without the noise occuring. I don't know if it is the turbo or not but it definitely happens immediately preceding the turbo whistle.

Now my immediate concern is that the turbo might be going. I'm not experienced mechanically so I don't really know but my mind has jumped to the worse.
I woul expect however that if the turbo was going then I would experience power loss and also that the noise would happen every time. The noise is intermittent and sometimes I can go a few days without the noise happening.
Here are my questions:

Has anyone else had this noise?
Is this a sign that the turbo is going?
Is it perhas a belt or something that just needs lubricated?s
My car has now covered 40k miles

*EDIT There is no smoke coming out the car

[Saint Steve]

Pcv failure or maybe Diverter Valve??

[Phil1980]

Diverter valve.

[Hurdy]

I doubt if it would be the diverter valve failing as MKVI's are fitted with the piston type DV.

PCV may be on it's way out, but yet again I don't think you'd get any noise from it anyway.

If you aren't suffering any power loss then again I doubt it would be the PCV or DV.

Similarly, a turbo on it's way out would be more prone to power loss, but could give a squealing noise.

I'd tend to look for things like the cooling fans or ancilliary belts for squeaks rather than the turbo, DV or PCV, however if it is definitely linked to revs on throttle then maybe it could be intake or intake manifold related.

[PenguinGTI]

Thanks, I'm away on holiday on Monday for a fortnight so I'll wait till I come back. It is not so much revs but more pre-turbo spool...

Ah well... if the turbo is going guess I'll just have to buy a new one.

KO4 conversion ha ha

[weston]

Mine has started making a squeak to, only when accelerating hard. Only since changing the DV for a revision d so I assumed this was normal. Hmm got me worried now although there's no power loss.

[PenguinGTI]

Mine has started making a squeak to, only when accelerating hard. Only since changing the DV for a revision d so I assumed this was normal. Hmm got me worried now although there's no power loss.

Can you describe this a bit more. What does your squeak sound like? Does it come in just before the turbo spools?

My car was an early mk6 build so originally came with the earlier revision DV however this was uprated to the more recent Revision D during a service. I really can't remember if the squeak arrived before or after the installation of the new DV.

[weston]

Mine has started making a squeak to, only when accelerating hard. Only since changing the DV for a revision d so I assumed this was normal. Hmm got me worried now although there's no power loss.

Can you describe this a bit more. What does your squeak sound like? Does it come in just before the turbo spools?

My car was an early mk6 build so originally came with the earlier revision DV however this was uprated to the more recent Revision D during a service. I really can't remember if the squeak arrived before or after the installation of the new DV.

Mines a mk5. I'll have a listen later and try to work out when it happens and how long for. It's more of a squeal than a squeak. I was told a while ago I could do with a new free wheel pulley. No idea what that is or if it could be the cause.

[weston]

The noise only seems to be in 1st from about 4500rpm