Spoke to a really experienced mechanic used to working with TDi's ..... he recons mine is due to slightly worn Turbo seals ...... he recon's it's nothing to worry about - unless the car starts to run on. Undo one of the intake hoses from intercooler (the one that goes over engine) and run your finger along inside bottom .... after the car has been left standing overnight ....... I bet you have a liberal coating of oil ..... mine has. Mechanic recond it could run for a couple of years before giving real trouble. This guy rebuilds turbos and recons Garret do a kit to recon this turbo ...... costs about £150 quid .... that does not include removing turbo!!! I know my car has suspect service history between 65k and 105k .... I suspect infrequent oil changes and inappropriate engine switch off has taken it's toll on mine..... I will leave mine unit she starts to run on...ulp.