[quote="henrym3"] Not sure you would hear any at idle and your problem is at speed and kickdown, If not absolutely 100% sure then I would recommend renewing vacuum pipes otherwise you could end up chasing your tail and spending big money. [/quote] yes only at kick down or maximum boost, then goes ...

it was built dec 2005. I've checked all the vacum pipes with a little pressure gauge and none is leaking. Also took off the little valve by the turbo and checked the little air filter etc, and vacum checked it. All good

Can't see any adrift or hear any air leaks

New turbo fitted but issues....Drives fine until kickdown then won't rev above 3000rpm, switch off & start up again and fine until i boost up, then won't go above 3000rpm again. Plugged in and showed 4521 code. Any ideas??

I haven’t got one there???!!!

Thank you. I’m expecting this to be the source of the problem then. It’s just a irritating low pitch whistle and when I take fuse out it stops, but no radio. Nav and tv still work though

That’s helpful thank you! Where is it exactly?

Ok, just spent nearly a grand on new turbo because of whistle in cab! Still whistling!! Took radio fuse out, fuse 73 in the boot compartment, and noise or whistle stops!! Could I fit a cheap suppressor to eliminate this, anyone know?

Have 2005 3.0 diesel. Had low frequency whistle inside cabin and was diagnosed as turbo. Had new turbo fitted, decent one from GSF, and it is EXACTLY the same! Anyone any ideas?