It's not just oil, in fact, most of what I've collected seems to be water vapor. Not sure, it doesn't seem to separate, but it's much thinner than oil.

I think the only path into the engine(except as below) is past the MAF sensor and through the intake manifold. Then it gets pushed past the rings into the crankcase. Then back into the intake and (mostly) out the exhaust. If a different amount of air flows by the (oxygen?) sensors than what the MAF reads, doesn't that set a code? and adjust the A/F mixture? I'm not sure, and learning also.

I have read about people changing from a turbo bypass valve to an atmospheric blowoff valve, and having problems(codes). I would think venting anything to atmosphere (running with filler cap off, loose valve cover) may cause a code. Someone just mentioned reading about someone else's misfire because of a loose valve cover. Didn't seem likely when I read it, but now...

Yes in stock config, metered air enters the crankcase just after the MAF sensor, through a fresh air inlet about 1/4" ID. I speculate that more air is drawn in through that at idle, when manifold vacuum is really suctioning the crankcase good.

And what i'm running now is the stock config, with a catch can added in each line.

 

On the 2.2L the crankcase vent feeds to the TB after the MAF. If that tube is broken or disconnected you get a code for vacuum leak because atmosphere is going in AFTER the MAF (too much air, lean at the #1 O2 sensor which makes the computer add fuel for a rich at the O2 sensor sometimes). Same thing if you leave the filler cap off, but not as much for some reason.

The only pressure comes from the moving parts in the crankcase and heat.

As long as the vent in the TB is blocked it doesn't care where the fumes go.

Water vapor in the PCV product sounds bad, where does it come from? Hopefully just from overnight condensation.

 

That all makes sense. The only metered air in your crankcase is from blow-by.

You're probably right, overnight condensation. I'm not catching a lot of vapor. My testing keeps getting interrupted by this oil filler cap problem, so I have to guess at about 1/2 ounce vapor in about 1000 miles. I collected much more on a rainy day, almost an ounce in 500 miles.

 

Since condensation is a byproduct of combustion it is not uncommon to see water vapors in the crankcase. Take the oil fill cap off and take PCV out of a valve cover on a cold engine and start it and you will see water vapor. I know that is another good reason we have thermostats to warm the engine as quick as possible so that water vapor doesn't condense into water droplets. I remember a few ford 302 cars that came in with the thermostats taken out and the engine would be filled with so much carbon and gunk, it was crazy. I'm sure other engines were effected, but the 302's were the worst I have seen. I think it's awesome your catching those water vapors. Your obviously doing something right. I can't hardly believe you could leak past the oil fill cap. Have you tried a new cap? Being plastic it could be warped or some other bazaar thing like a small crack in it. A new o ring may not be enough. If you had enough blow by to push past a oil fill cap, I would guess you would have bad oil leaks from easier places to leak from, like the valve cover gasket. If you have tried a new cap, I am sorry for bringing it up. Keep up the good work. I'm learning also. Thanks!

 

No I have not replaced the cap itself yet, good suggestion. Nothing visually wrong with it, but there could be some unseen damage. I'm going to try a couple other things first, bypassing the turbo-side catch can with just a short hose, like GM designed.

Used to be 8"-10" of hose, now it's 7' of hose, a catch can, and a 3-cup collection tank. I think it may be just too much for the turbo's weak vacuum to depressurize in the few seconds that it's boosting. I may try a check valve between the catch can and collection tank.

I don't know, maybe that makes no difference in evacuating the pressure. Maybe I need to take apart that system and inspect it closely.

 

I can't say it won't make a difference. I have had my single catch can on the turbo side for a while now. I have the can placed next to the battery. I have no problems that have been seen yet. With my new engine install I will use another can on the PCV side, manifold blocked. I just feel two cans will be best. Caps are pretty cheap and easy to change. I'm sure you will get to the bottom of this.

 

Here is a Napa part# BK 7031710 if you wanted to go after market. I have been a bigger fan of factory parts. 12594232 for a gm cap. I new you could find them. I was just board. :)

 

As Don states, I can confirm on the 2.2l 2007, mine is sucking oil out of the valve cover tube in the left side down the hose and into the fitting in the elbow just before the throttle body.
Now it sucked oil there when I ran the stock paper filter and stock air filter box, and the drop in K&N oiled filter ( cleaned and very lightly oiled) and now even with the K&N FIPK set up with the filter cleaned and very lightly oiled!
Here's the kicker, Sweetie's Sunfire GT 2.2 has the same valve cover port and a K&N drop in air filter, but no oil sucked into the hose! Same amount of miles 210,000! Hmmmm

 

RJ RS SS 350 just wondering if you have any new reports on your issue?

 

Sorry I haven't posted on this for a while, I've had to relocate to Texas for a temporary job. I'm in a motel for a bit, so I really can't do anything right now.

Before I left home, I abandoned in place the turbo-side catch can, utilizing a short piece of hose from port 2 to the turbo, just like the General had it. The oil filler cap showed only the slightest oil residue around it, so I do think the leakage is at boost only. It was a short-term test and I didn't spend much time boosting, so still kinda inconclusive.

Then I plumbed the catch can back in, and installed my extra check valve between the catch can and the collection tank, hoping that would make it easier for the turbo to depressurize the catch can system. Then I left for Texas.

The problem is still not solved. After about 1,200 miles, I had lost 1/2 quart of oil. Haven't checked the catch cans yet, don't know how much went into them or how much escaped past the filler cap.

From the residue, it doesn't seem like all that much escaped past the filler cap. In the 700 miles since I topped off the oil, I haven't lost a bit, oil is full.

Driving conditions were much more strenuous in the first 500 miles of the trip. Climb up Tehachapi (3,500' climb), climb again from Baker to Mountain Pass (3,000' climb), city and freeway driving in Las Vegas. And it was running a little hot in the desert(220*+). I kept turning off the AC to help it cool down a little. I even turned the heater on and put the windows down a bit at the worst point. I was concerned that I might have had an air bubble, but I think it was just miserable hot. All this may have caused more blow-by/consumption.

I need better catch cans, some of the vapor is getting past the filtration media.

I'm at the point where I think a vacuum pump might be my only solution for this excessive crankcase pressure(or a new/rebuilt motor). I need an education.