Hello.
I have an Audi A3 2.0 tdi s line 2006 plate. When I accelerate the car makes a loud whistle sound exactly like a siren from a police car. I have taken it to a few garages local to me and they have said different things.

When i disconnect the plate of 6 or so small pipes going into the vacuum solenoid box and accelerate slightly there is no siren sound at all. Does this help narrow down the problem?

There is is no loss of power, no limp mode just a little bit more sluggish to pull out of a junction than it used to be.

I am am adamant the turbo is okay and it isn't the bindings. I had a major service done from Audi main dealer and with the health check they mentioned a boost pipe clip was broken. Can some help me as to where I should start at finding the problem? I can't seem to find a broken boost pipe clip or see any leak!

Thanks

 

I would start with Diverter Valve.

 

My 2006 2.0tdi is doing exactly the same. My son looked for the policecar first time he joined in the car :-). A mechanik told me its normal?