GT4 Celica intermittently smoking - suggestions?

[Barclay]

Previously the car was blowing smoke, turbo was leaking oil internally, so got turbo rebuilt (seals were stuffed and shaft was bent). Back in now, been in for a week.

But now I get smoke (seems white, stinks like oil) intermittently. Basically:

On first start up - no smoke

When car's cold - no smoke

When car's driving - seems like no smoke, but wouldn't see it if there was anyway.

When car's hot and idling - sometimes smoke, seems to be connected to if positive boost was reached.

When car is switched off but running on turbo timer - smoke starts coming out back, almost immediately

The car idles about 500 rpm higher on the turbo timer - I'm running 15W-40 oil.

Car has been sitting for about 20 minutes since i got home. I just started it, ran for a minute - no smoke. Ran it on timer for another minute, still no smoke. Engine is at operating temperature still.

Oil level is dropping, so it's not just oil in the intercooler. I was thinking maybe blocked return line, but i would have thought it would be more regular if that was the case? And valve stem seals, generally it would smoke on start up. This one's clean every time.

I'm out of ideas... anyone got any suggestions?

[T.J]

nicorette patches?

nah seriously sounds like oil might be leaking past the impeller seals just see if you can take off the inlet tract before and after the turbo if there is traces of oil before the turbo then its not the turbo but if there is oil after the turbo and not before then its probably the seals they could be leaking if the return line is blocked and the oil is building up too much pressure in the turbo