Volvo Repair: 94 850 turbo sean, leaking oil, myra myra, valve cover gasket

Question
I have a 1994 850 turbo sedan.When I bought it the turbo was replaced with a used turbo from a car with 130 k. The oil leak is recent and I'm am told it will take at least 2 hrs to diagnose. The car still runs very well and no sign of problems with smoke.The work was done by a volvo mechanic. How concerned should I be? If this is an early sign of the turbo going bad, how quickly do they go? The oil return line was dry as was the valve cover gasket.

Thanks for any info you can provide.

Myra

Answer
Myra, there is no valve cover gasket per se.  Its a chemical gasket and they dont usually leak.  Turbos on those cars dont usually go bad.  Who told you it will take 2 hours to diagnose?  Joe's garage or a Volvo tech?  Generally the 850 leaks from the rear main seal, rear cam seals or the front cam seals.  The turbos pass oil sometimes but that is normal.  Let me know.  Roger