I've been chasing this oil consumption issue for some time now and the problem is that the engine consumes about a quart every 4-5k miles. The car is a 2014 Skoda Superb 2.0 tsi CCZA 200hp motor with 60k miles that I've had for the past 10k miles. There are no leaks from the valve cover, head gasket, oil pan, main seals and nothing drips on the ground. There is no smoke from the tailpipe at any load condition.
The only place where there is oil seepage is where the rear breather tube from the fine oil separator connects with the intake duct just above the turbo. I've not tested compression, but there are no issues with ignition or power - the engine is silky smooth and I've tested it on a dyno and it puts out a healthy 223 hp max, as these motors typically do. So I don't think the piston rings are worn and I don't expect it to have excessive blowby across them that would explain this issue.
The first thing I've done is change the air filter as I thought that it might be clogged up and enough vacuum was created that would pull too much vapor from the crankcase when the engine is at boost. The filter didn't appear dirty, but anyway replacing it did not fix the issue. Then I've bought a new OEM pcv valve from the dealership and replaced it myself. The old PCV valve appeared to work ok, but quite a lot of oil dripped out on the ground - maybe a couple teaspoons. Unfortunately, the new PCV valve did not fix the issue.
So I'm thinking there are two possibilities left. One is that the oil return line from the pcv valve to the sump is blocked. I didn't see any oil standing in the port in the valve cover where the cyclone funnel in the pcv returns the oil. The other is that the turbine side gas seal is faulty and some expanded exhaust gasses find their way thru there, across the bearing housing and into oil return line, picking up an oil mist along the way, and then are evacuated thru the pcv valve in front on the compressor side of the turbo. Is there some other possibility? Does anyone know if the stock IHI turbo uses a piston ring or some kind of labirynth seal design? Is there a way to test this theory without disassembling the turbocharger? Or did anyone else run into a similar problem and fix this issue? Thanks in advance.