Upper bearing (turbocharger)

The upper bearing of a turbocharger supports the rotor at the compressor end, opposite the turbine-end bearing in the hot exhaust gas path. On overhung axial designs both bearings sit on the cool air side; the upper or compressor-end bearing carries radial load and, in many MET and TPL units, part of the axial thrust through a thrust collar. Bearings are plain white-metal sleeves or, on some MAN ES units, rolling-element cartridges, lubricated by engine system oil or a self-contained sump. Bearing clearance and oil supply set rotor stability; wear shows as raised vibration and is a scheduled overhaul item.