Федор, для Вас специально выдержка из ТРI (Technical product information) "Boost air system - oil leaks":
It is normal for the boost air system to be covered by engine oil. After turning off the engine the oil gathers at the lowest point of the boost air system.
In this case a replacement of the turbo charger is not effective - groundlessly replaced parts will be redebitedИ не парьтесь по этому поводу.