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Proper PCV-to-Crankcase breather tube info....

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
I find having to post this info numerous times. So I will post it here so anyone can just share a link when trying to explain it in the future.

There are two designs of PCV and two rear breather tubes.
Both PCVs will work with the valved rear tube.
But if you have the open rear tube...only the PCV with a check-valve placed where it recycles vapor through the valve/rocker cover works.

Also....if you have a recycling catch-can or PCV delete plate, you should run those with the open rear breather tube. This valved-PCV is meant to be paired with the open rear tube...but it will also work with the valved rear tube (just means there are two valves in the recycle to turbo inlet path).

Valved-PCV
06F129101N.jpg

↑ (or recycling CatchCan or PCV delete) to be paired with the open rear tube ↓
06f-103-213n_1.jpg

The Valveless PCV
pcv.png

↑ to be paired with the valved rear tube ↓
06f-103-215-b-_1.jpg
 

Saki Ashraf

Passed Driver's Ed
Location
Houston
ROH thanks for posting this very useful info.

I installed a recirculating catch can system about 15K miles ago on my 2007 FSI GTI and never checked this rear breather.

Currently in the middle of a K04 upgrade and went to check that rear tube after reading your post. It is a valved tube. How would this affect operation of the PCV system? While removing the turbo I did notice excessive oil on the turbo inlet housing and backside of motor - could this be a result of having a valved rear tube combined with a catch can?

Thanks for any comments/insight.
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
The valved rear breather tube(RBT) opens when the crankcase pressure is high. When pressure is low, the valve in the RBT will not be completely open and allows condensation in the crankcase to take more time to evacuate. The oem PCV is designed to switch vapors, to be recycled, over to the intake manifold for the strong vacuum at low rpms so to remove them. With the connection to the intake manifold removed for a recycling catch-can or PCV delete, the vapors can linger in the engine much longer. With the RBT open, the turbo inlet will draw the vapors out more efficiently. Plus...you never need to worry about the RBT valve sticking shut.

Years ago...many were simply removing the valve from the RBT to avoid buying another. I believe they would cut the center portion out while leaving the outer ring of plastic. in fact, here is one thread/topic on it; https://www.golfmkv.com/forums/inde...er-tube-check-valve-for-bsh-pcv-revamp.55635/
 
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