If it becomes clear that the turbocharger is not operating as it should be, a diagnostic test should be carried out as soon as possible. Early signs of trouble in this regard include a lack of power from the engine, possibly accompanied by a high squealing sound from the failing turbocharger bearings.
If caught at an early stage, it’s possible that a replacement unit may be all that’s needed. If the problem is ignored, the turbocharger can completely let go, taking the engine with it.
Turbocharger failure is particularly common in ex-fleet cars, which often have doubtful service histories. As we have often pointed out: skimped servicing almost always results in serious and expensive problems further down the road.