Philip Deg

I am concerned about all the carbon deposits that are likely to be deposited on valves in a DI engine.Does the C200 cgi engines 1.8l turbo have any built-in safeguards to minimise this issue or do I have to install a catch can to address this issue? Where do I install a catch can if I must, and, will it trigger any worrisome code. Thanks for any positive replies.

Adi-Benz

Built in air-oil separator.

It has like 3 different names but it's there.

W204Motorsports

From the amount of oil I see in the intake manifolds on these cars, I rather be safe then sorry. My catch can catches about 100ml of oil every 6000km. With all the plastic flaps and what not in the manifolds, not to mention deposits, I rather catch that oil before it gets to those parts and contaminates them. If you chose to do so, you just have to T in the catch can to the hose coming out of the original air oil separator.

superangrypenguin

I wouldn't waste my time. This topic has been discussed to death on here so I'll just leave it be.

Philip Deg

Thanks a lot ; this will certainly allay my fears for some time. I will purchase a catch can and install as advised. many thanks............

superangrypenguin

Unwarranted fears imho. The engine already has a built in one. But hey. Different strokes for different folks.

W204Motorsports

^This. I don't have any proof of it preventing deposits or reducing them but it sure keeps my intake system oil free. Be sure to replace your air separator canister regardless before 200k. Dealer said they don't service them but I pulled mine at 180 000km and it was extremely dirty, contaminating everything since it just holds the oil vapors/gunk without being able to drain/clean it like a catch can.

superangrypenguin

Curious, why not just pull the air oil separator from the engine and leave it sitting overnight in a carbon cleaning solution? E.g. why replace it if you can just clean it?

Adi-Benz

Mine had a small leak

Easy job, I wrote a diy on the forums here

I know, I answered his question for myself lol

W204Motorsports

I did try to clean it and left it in a solvent all night and when I tried to rinse it, debris was still coming out. There's only two small holes so you can't even get to the inside to clean it properly, I wasn't able to brush the inside so I just replaced it for safe measures, they aren't expensive at all and aftermarket ones work just fine.

W204Motorsports

I remember that thread but you are confusing the breather vent and the oil separator.






^ This is the actually oil separator where you would T in a catch can from the hose coming out of it, oil comes out of it and goes into your intake. What you replace is just the fresh side breather for the pcv system.

Adi-Benz

You're right. They use the same and different names for so much of this stuff. Air oil, crankcase, blah blah