Your can doesn't come apart using a 3mm allen wrench?
Picture please.
I got one from EBay for $20 and some place on this forum I showed what I did to it.
I think it's in DIY section. Navigation on the forum isn't my greatest.

Pictures in post # 1,3 and 6

Is this your catch can / oil separator?

http://s697.photobucket.com/user/Ric...hgsbk.jpg.html

I think the difference would be your dealing with turbo pressure and mine is just a 2.2 litre, not much pressure.

Here is Cat Man's thread https://www.chevyhhr.net/forums/how-...-can-ss-54374/

Yes, I recall that thread, it pertains to the 2.0 Turbo SS oil build up .

Yes

Oldblue .The lower on the car you can get the catch can the better. You might want to put baffles or stainless steel wool in the can half way up in it. When the oil/air passes through the can the oil needs a media to attach to.If not it just stays in the air and passes through. I put my can behind the front bumper. No oil in the intake.

Yes, but for my climate, ffffffffing ccccoollld, I did not want condensation filling up the separator can and freezing , resulting in a split open can , a waste of $20 bucks and me kicking myself 'cause I forgot to drain the catch can.
I'm just 575 miles into this and temperatures ranging from 48 F last week to 10 F this past three days, so far no oil or water has been sucked up the hose to the catch can, or out to the throttle body.
There is no condensation on the underside of the oil filler cap either. So far, this set up is working , at lease for my 2.2 N/A Ecotec.
The throttle body is clean, the exhaust tip is not sooted up, and that P0420 code hasn't popped up. It usually came on within 75 to 100 miles of clearing the code, also, I checked for pending codes and there are none!
I'll keep on reporting any changes.

I'm sure you verified that the air flows through the can. It just seems odd that nothing is even coming into the dirty side line. Your anti-Newton design was still letting oil vapors through, right, that's why you went to this?

Well , yes the other hose and loop system did let vapour to suck up then slide right on down into the fitting with the white teflon tape in the right by the throttle body.