The turbochargers generally fails as a result of an incorrect oil supply. This is due to the fact that the oil inlet pipe is easily blocked, having a very small bore and 90º angles. The oil gradually solidifies inside the pipe, blocking the oil inlet and finally causing the shaft to seize up. It frequently happens that, on shaft seizure, the screw thread shoots out and damages the inlet turbine.
Whenever the turbocharger is replaced, we would recommend replacing the oil inlet pipe. If this is not done, the pipe should be thoroughly cleaned and inspected for blockages.
If these instructions are not followed, there is a risk of the turbo breaking down after just a few miles.