the white powdery coating is probably residue left from traces of coolant leaking from the cooling pipe banjo's.. You will probably never see the leak as it evaporates as fast as it leaks.. If you undo the coolant pipes from the turbo, you'll probably find the aluminium sealing washers are cracked. Nowt to worry about really, but if you do decide to undo them to have a look, make sure you have new replacement washers first They are only pence form Ford, but you will have to fit new ones if you undo them.