[Maestro]

Couple of weeks ago I did an water pump and Oil Filter House Gasket change on my 07 335I. During the process I discovered lots of oil in the Charge Tube going to the throttle body.

As I learned this is normal due to the crank case ventilation systems used on the 335I. Everyone claims the BMW design it flawed and you need to put in an aftermarket catch can like the one from BMS.

http://www.burgertuning.com/BMW_335_oil_catch_can.html

I found this BMW training manual

http://prodcds.bmwuniversity.com/lib...Mechanical.pdf

On page 26 they talk about their cyclone oil separator and show how it suppose to work. Their design is no different than most oil separated that exist for lots of applications even for air supply systems for paint spraying.

I do not see the specific flaw in their design and how a BMS catch can would be any better. You can see from the BMW design they have check value that lets the built up oil return to the engine. If this is stuck then maybe that is the issue. I am not sure where that value is to check it and see if it working properly.

It also show the crank gases flowing two different direction and have check values and says that if they are stuck you can have excessive oil usage and these should be checked and replaced if necessary.

From what I saw in the BMS installation guild it does not hook up to the two different flow paths that is in the 335I ventilation system so it may work in acceleration but not deceleration or vise verse.

For those who put in a catch can have you seen a decrease in the oil in the charge pipe as well as decrease in the carbon build up on the intakes valves. My fall project for my car is to clean the intake since they are all carbon up and I am deciding on weather I need the catch can and I am going to do at the same time.

I now know that when I had an issue with all sorts of codes being thrown and the VANOS having issues BMW walnut blasted the intakes and never told me this I know for sure since I found pieces of walnuts all over the block.