Turbocharger Bearing Failure
The engine's oil lubricates the turbocharger. It's vital to change the oil and coolant at recommended intervals, because old and contaminated oil damage a turbocharger's bearings. Today's turbochargers spin over 100,000 RPM. That's incredible! These speeds, combined with the hot exhaust spinning the turbine wheel, create substantial heat.
The engine's cooling system removes this heat. It's why many manufacturers recommend cooling the turbocharger by idling the engine for a minute or two before shutdown. When the engine is shut down immediately after an average drive, the oil hardens, and little pieces get into the bearings, causing failure.
When the bearings are faulty, a whining sound can be heard. It also damages the shaft and housing. As the bearings wear, the blades on the turbine and compressor wheels can get damaged from the excessive end-play.