no not a faster way for retards to communicate with fellow retards but the noise a wastegate makes when you come off the throttle,well my van has started doing it,it,s a transit connect TD,is it about to explode?
still goes like a stink tho

Wouldn't have thought so... Maybe a sticky flap of some sort?

Sticky flaps? Might want to see a Gynocologist about that...

The exhaust is in the process of breaking just after the turbo. Don't ask me how I know.

sounds like a jammed recirc valve causing turbo chatter

My striker does it cause I ditched the dump valve,I quite like the sound tho,it sounds like a pigeon cooing just before a 12 bore shotgun each gear change,escort cosworths rally car style!!
could be vacuum pipe off your dump valve or blockage in the recirc pipe from it maybe.
Chris

As Mike said its more likely to be a leak on the exhaust side, if it were on the compressor side you'd probably be down on power and be seeing lots of grey/black smoke as it would be likely to knock the fuelling out.

If its the sound you describe its the turbo stalling when you shut the butterfly, sounds like your recirc valve is shut so the air is locked in. Kills turbos after a while.

The term 'Turbo stall' is very misleading as the turbo doesn't stop spinning, it just naturally slows down as there isn't the same level of exhaust gas driving the turbine when you have closed the throttle. Chattering from the turbo during throttle off is a acoustic effect of the pressurised air from the turbo, suddenly meeting a closed throttle and bouncing back into the turbo compressor. The sound is really called turbo surge and its best avoided as it can cause excessive wear on the turbo bearings. Depending on how your engine management works, this excessive air pressure can cause fuelling issues when the throttle opens again.

Your recirculation valve is there to balance the pressure in the inlet, triggered when the engine manifold pulls a vacuum.

she has only done 5000 miles
i think i may have consigned her to an early grave,ill have words with "maintenance" who will tell me to drive it till it stops no doubt

If there's 5000 miles on the clock take it back to Ford