Hello, what you can do that you have oil in the hoses of the turbo (surely in the intercooler also) can be a problem of breathing of oil vapors (PCV), also a scarce piston-cylinder wear can make these gases blow towards the admission. I will tell you an experience with a C-4 that happened the same; The thing was that the nuts of the injectors were lazy, with this some injectors escaped compression but since they carry a retain in their upper part they did not let this outside out but that it is accumulated in the upper part of the cylinder head (this goes in two halves) thus passing all the oil vapor opening the PCV valve of row Encuarrinando more the admission collector when this steam was mixed with the gas of the EGR ... You do not imagine the weight that the collector had and the conduits of the butt of the amount of shit that there was there ... to clean everything. Changing nuts and the copper joints of injectors were solved the entire problem in this 1.6 HDI, in the case of the Musso, it would also have to be ruled out on the turbo caps. Luck!!