[armend195]

Seems like there are many opinions about deleting the ccv & venting to atmosphere (VTA), either via catch can or directly from Valve Cover. I can’t find anything conclusive. What are your thoughts about this?

Car in question:
2005 325i - N52 with magnesium valve cover & CCV/oil separator under the intake manifold.
260.000kms on the clock
I live in Sweden and we have cold winters sometimes hitting -10 degrees celsius.
It is my daily driver.

I suspect my ccv is failing because i get a fair amount of oil in the intake.
One option is to replace the CCV completely incl all hoses etc. Expensive if going genuine & i’ve read OEM stuff does not hold long.

I might choose to go VTA temporarily. Some say it has effects on seals etc since there will be atmospheric pressure in the crankcase. Some say you will have rough running and engine will work harder - while others state it’s working flawlessly and sometimes even better performance due to vapors not mixing with air from intake.

If going VTA my plan is to seal the intake port, seal the ”oil return” pipe from the sump and simply run a tube from the valve cover, possibly through a catch can, down under the car somewhere.

Now, my only question is regarding the crankcase pressure?
The engine is NA, will there actually be any noticeable difference if it is VTA and having atmospheric pressure? I mean if pressure increasws slightly in the crankcase it will find itself out through the tube? It will not reach the point of blowing gaskets etc? Or am i wrong?

It is also possible to run the oil catch can inline to the stock CCV or directly into the intake. But if i’ll tackle this job i’d like to remove the possibility of oil entering my intake completely!

What are your thoughts and experiences? Thanks in advance!