Volvo Repair: Turbo passing Oil, oil types, v70r

Question
I have a 1998 V70R AWD (87K) and I rencently took it in for a service. The mechanic reported that the car was smoking. I have not noticed this before or since. Later the mechanic mentioned that possibly due to the car sitting for a long period at idle that this may have caused the emissions build up in the Turbo and thus making the car to smoke when accelerating away.

They did mention that the last time the oil was serviced there was a Synthetic Oil used and they have now replaced with traditional (required) oil?

I have not seen this smoking problem and I am pretty maticulous with my cars. I have driven behind the car and have not seen the car smoke.

What is the history and life expectancy of a Volvo Turbo? Where could the smoke be coming from? Change in types of oil? The mechanic mentioned it may be passing Oil. Not the first they have seen and they could tell me whether or not it would worsen or if it was from changing the Oil type.  

Answer
it is not required to use regular oil in a turbo.not sure where they got that from.the life of the turbo is greatly affected by the way it is maintained.I would say about the mileage you are at to well beyond 100k or 150 they could last.depends on how they are driven and how they are maintained.it would not be unheard of for a turbo to go bad at the mileage you are at.I doubt it is the changing of oil types.If the turbo is bad it would be leakign past the seals.