Turbo on D3 do they limp home?

Have just had ALL belts, idlers, pulleys, tensioners etc replaced on motor (front and back of engine, and full new transmission, and all 4 wheel hubs as well, and new alternator and water pump, and fuel pump.
(All in same service, just to be sure.)
Cannot be much left that could go wrong, but I'm an optomist.
The "noise" seems to vary with either the day or whether I use aircon, and I am starting to suspect the aircon compressor (thanks for alerting me Graeme) as vehicle has done 320K's and things are starting to be due for overhaul.
Still looking and listening.