[ChevyGuy]

turbocharger failure up to 100,000 miles regardless of the year of the vehicle.

100,000 miles up to 5 years, yes. 100,000 at 7-8 years? I don't think so.

my mechanic said there is oil in the inlet that is a sign of imminent failure.

Exactly where was it found? It might be a sign of PCV failure (common in the 1st Gen Cruze).