johnoconnor

Hi gerryh, My '03 115TDi was doing the same thing occasionally. Apparently the Turbo Boost is controlled by an adjustable vane mechanism which is prone to sticking if the car is doing a lot of light work - town driving etc. Other members with similar problems suggest giving the engine a "good workout". This advice seem to have worked for me. No recent issues.

I have the same noise. It turned out to be the booster heater located underneathe the car. It is automatically started by the electronic control unit at a preset value of engine temperature and outside air temperature so you can't switch it off.(Not to be confused with the Auxillary Heater which is located inside the car for the rear passengers). Apparently the TDi models are so fuel efficient they dont generate enough engine heat to heat the interior for some time after start up. Hence the requirement for a booster heater.