Originally posted by inspyral
If you did that, oil would stay stuck in the drain line, at a height equal to the level of the oil in the pan, and might even back-up into the turbo's CHRA. This will prevent the turbo from draining properly, which could cause the oil seals to fail prematurely.
I suppose that this could apply to overfilling when changing your oil as well, right? I think I just screwed up my new turbo by doing this. I recently switched to a LS/VTEC setup (really I have all GSR internals in a B18A block... long story). Anyway, I changed my oil after the engine's first 30 minutes of running. I have the Moroso oil pan, so I filled with 5.7qts, forgetting that now I have oil feed lines to the cylinder head as well. I think I've ended up with an oil level that reaches the turbo drain plug. I'm about to find out in a second for sure, but I can say that oil is leaking from the discharge side and from the front of the turbine housing where the v-band is... a brand new turbo, possibly shot! GEES!