Whistling at idle (intermittent)

[stupot]

Hi All I’ve searched but can’t quite find anyone that’s had exactly this…
2017 204 DSG 4m 78k miles.
Intermittently I’m getting a faint whistling noise at idle, it’s possible it’s doing it at other times but only notice it when stationary. It sounds like wind whistling in a tunnel (best description I can think of!) It’s not the heater fan (or at least when I fiddle with that it has no effect on the noise), pretty sure it’s not belts as had cambelt and aux belt+tensioner done recently. Stops when I pull away.
Obviously it doesn’t do it when I show the tech at the garage…
Any ideas welcome, no other symptoms and it’s quite faint… but it’s annoying me.
Thanks in advance for any ideas. Stu

 

[DXX]

Try recording it and posting it on here. Obviously when you say ‘stops when I pull away’ could be just a case of being outside audible range or masked by other noise.
As for eliminating recently maintained components, human intervention has a habit of creating more problems if done badly.

 

[stupot]

Thanks, good point on work being done and the risk of an error. I’ll try recording it.

 

[Amymax18]

I've also had this intermittently, same engine. I thought at one point it was when a regen was taking place, not sure why that would cause the noise though - possibly fan going like the clappers ?!

 

[DXX]

Engines and their systems do make many different noises, just be aware that the sound proofing on a commercial van is nowhere near as good as most cars so you will hear them.