Oil leaking into the inlet of the turbo

I wish I had a diagram.

This one will help for understanding a non-turbo engine:
http://www.autoshop101.com/forms/h63.pdf

Most cars draw a vacuum through the intake manifold, and PCV gases from the top and bottom of the cylinders that escape past the valve seals/rings are simply drawn into a loop by vacuum that is then recirculated through an EGR or PCV system and re-burned in the cylinders before being pushed out the exhaust system. Simple, cheap, and it works. Not terribly efficient - some oil loss occurs as a result of this, and the intake manifold and/or air filter are gunked up over the years.

Since the intake manifold on a turbocharged car does not produce vacuum when the turbo is boosted up, there needs to be a 2nd source of vacuum. You guessed it...the turbocharger, like a big vacuum cleaner, provides tons of vacuum at the intake side. So the Cruze simply has a 2nd hose routed there. That results in a little oil in your intake hoses, in addition to the oil that escapes past the turbo seals when boosting heavily and then is blown through a loop through the intercooler and back up to the throttle body.

It is mostly fine droplets of oil, but they do settle over time. It is this exact reason why catch cans are a common "mod" on turbocharged cars. Running higher boost pressures on tuned cars results in more "blowby" in the cylinders and more oil blown past the turbo seals as well. People don't want that oil gunking up their intakes and cylinders, so they separate out the oil vapor into a canister that can be emptied later on. It is typically just spliced into the PCV line that dumps vapors back into the intake manifold. Air into the engine, oil out into the canister.

My last car - a Volvo - had an "oil separator" box tucked under the intake manifold that served the same purpose as one of these catch cans . I believe Saab or BMW used a similar system on some cars - but I can't remember which. As typical for these brands, it was an over-engineered system that served to minimize oil loss, but required maintenance in the form of removing the intake manifold and cleaning the system in 100,000 miles. Most people wouldn't want to pay for that kind of service - just like people hate changing timing belts.

This system brought in oil vapors from the tops and bottoms of cylinders via the "hose to valve cover" and "hose to engine block" (from the bottom of the cylinders). It pulled a vacuum through the other hose on top of the canister from the turbocharger (to PTC nipple at the turbo). Finally, oil droplets settled to the bottom of the canister and were returned to the oil pan. There was also an additional small vacuum hose that led to the turbocharger from the intake manifold to provide vacuum for the system when the engine was at idle and the turbo was not providing vacuum. Great in theory, but it does clog up and require maintenance every few years - especially if conventional oils that sludge up are used instead of synthetic. When working correctly, this will keep most of the oil out of the intake hoses/manifold.