My original OCC install consisted of the catch can connected to the line feeding the turbo inlet, nothing else. This means the hose from the valve cover to the intake manifold is still in use. After several months of driving with the OCC, there was still no oil showing on the OCC dipstick. After seeing several online posts with pics of their catch, I did some research. According to the Bentley manual, the line to the turbo is used when manifold pressure is â€œunder loadâ€. The line to the intake manifold is used during â€œdeceleration or idleâ€. Since most of my driving is not under load (I use a lot of cruise control and highway driving), the OCC wasnâ€™t getting used. So, the question is, should I cap the manifold line, or route it to an OCC? Because of cost and ease of installation, I took the cap option. Bought two vent caps from my local Audi dealer, part number 036131510, removed the hose, and installed them. Peugeot also sells them as #0361.S4, and ECS Tuning sells them online, all for about $10 each. Didnâ€™t take long to catch oil in the OCC. Hard part is figuring out how to remove the hose without breaking it. Once you see how the vent cap is designed, itâ€™s pretty easy to figure out. After a couple tanks of gas, I noticed crankcase oil level was down a quart. This is the first time this has happened - this engine hasnâ€™t burned oil in the 20K miles / 2 years Iâ€™ve driven it. First guess is crankcase pressure is forcing oil past the valve stems into the combustion chamber. This implies the vent plugs I just installed messed things up. So, I ordered a Dual Boost Tap, bought some hose and a â€œteeâ€ fitting, and connected the rear (passenger side) valve cover outlet to the existing OCC. While in there, I disconnected the turbo air inlet hose for a quick look. Worst fears realized --- oil puddle in the air chamber! Made a couple calls about turbo repair / replacement. One shop that knows Garrett turbos, told me that high crankcase pressure can cause oil to â€œbackflowâ€ thru the turbo oil drain line, and cause the symptoms Iâ€™m seeing. Resolve the high crankcase pressure issue, and the oil consumption problem will go away. Then thereâ€™s an oily mess to clean up --- from the turbo air outlet to the intake manifold. This is several months after the initial OCC install. Iâ€™ve created the very mess the OCC was installed to prevent! The WMI system should keep the rest of the lines clean, once the oil source is removed. After reading some of the various threads on OCCâ€™s, oil consumption, and bad smells, itâ€™s my guess that they have a similar problem --- 2 vent caps installed, or a dual boost tap adapter connected with the plug installed. I still donâ€™t understand how this adapter can read boost when itâ€™s connected to the crankcase / valve cover vent line. Maybe if installed at the manifold end of the hose and then plugged, but I donâ€™t know whatâ€™s happening inside the throttle control box. Anyhow, I installed a BSH Dual Boost Port Adapter on the valve cover, in place of the hose --- plugged the boost port connections, but not the main vent. Then routed a hose from this adapter to a â€œteeâ€ I added to the OCC inlet hose. Iâ€™m trusting the Bentley manual when it indicates that only one of the two vents are active at any time. After a lot of oil cleanup, a month or so of driving, and a couple tanks of gas, there seems to be no more oil consumption or leakage thru the turbo. Itâ€™s pretty easy to remove my turbo inlet hose to check it. There are those who say Iâ€™m â€œall wetâ€ with this theory, â€˜cause theyâ€™ve had virtually no problem with their OCC single line install. Itâ€™s my belief that itâ€™s all dependent on driving habits --- with the rear â€œlow pressureâ€ vent plugged, there is little or no pressure relief in the crankcase, so it builds up until it finds a path out --- in my case, the turbo seal. Iâ€™ve read where others have leaking valve cover gaskets --- another probable pressure relief path. My valve cover has been removed / replaced a couple times, so not a weak spot. The â€œburning oilâ€ smell often noticed, in my case was probably from the oil puddle in the turbo air inlet chamber. When the engine is off, fumes can escape thru the air filter. There was also oil residue on the turbo outer surface, and the oil hoses arenâ€™t leaking. S, the reason for this post is to offer a solution to those of you with similar â€œsudden oil consumptionâ€ after an OCC install.