Burning oil when opening the oil filler cap


New Member
Apr 22, 2022
Hi all,

It's been a while, busy with trouble shooting small things.

But now something strange happened and i hope for other experiences.

I have rebuild my engine with forged Pistons and rods, as well as closed deck conversion with bw s200sxe. All seals bearings etc all new. Since all is together i drove it about 30k km. Oil consumption used to be very moderate on 10k probably 0.5-1l.
Than i got squealing from the seals so i went ahead and had valve cover and water pump replaced. Water pump was disturbing the LIN bus from time to time.

After that my car suddenly started to eat a lot of oil.
When the engine is warm and i open the filler cap. I see no obvious blow by and it pulls strong vacuum, however when i open the cap with running engine it starts smoking blue. Close the cap it stops.
Can confirm it's not overfilled with oil just drained today because i didn't believe the sensor already.
Power is good. I would normally not expect an issue with any seal as they are all just a bit over 30k km.
my ideas would be insufficient turbo drain or supertech valve stem seals aren't good, or the guys messed up something when they did the valve cover (oem bmw parts).
Is there anything going with PCV that could cause it?

Thanks for your ideas!