Blow by - post catch can & PCV delete


Registered User
Hey people check out this video. Not done a compression test but what other symptoms would i be seeing/feeling due to bad blow by?


Alex C

Well-Known Member
VCDS Map User
was it like that before the catch can/PCV delete?


With the stock system you have the inlet manifold relieving that pressure under vacuum.
In simplifying the pcv and catch can you've blocked that up so the only pressure relief is via the cam cover breather outlet.

Will it cause probs, I like to think not, not enough pressure in there. And it's also not connected to the cylinder in any way, so in no way can it represent blow by.


Registered User
Not sure if it was like this before. I only noticed now after doing the catch can. LOL

So because I blocked the centre nipple off and deleted all that pipe work from the bottom breather as well the air will go up?

When oil cap is shut then it should all go toward the catch can yeah?