While the engine is running and oil is fl owing through the turbo’s bearing system, most of the transferred heat will be absorbed by the oil, preventing damage to the bearings and oil seals. Once the engine is shut down, the oil fl ow stops and so does the exhaust gas flow through the turbine – but all of that heat stored by the exhaust manifold and turbine housing still remains. This heat must go somewhere. Its only escape paths are either to be transferred via conduction into the turbo’s center section and the exhaust downpipe, or to radiate into the surrounding air under the hood. A small amount of heat will be transferred to the surrounding air via radiation and convection, but the great majority will conduct from the turbine housing into the center housing, since the center housing is at a lower temperature. Additionally, some of the heat will travel from the turbine wheel into the shaft and out towards the bearing system