Crankcase Ventilation Flow Diagram

[UrS4boy]

Its on the diagram

FUUUGGGGG

Thanks. Duh. I didn't mean that

I will fix it ASAP.

(But not easily).

[UrS4boy]

Fixed it. Wasn't that bad. I had it posted in three forums so that was the biggest problem.

Thanks for pointing out my mistake.

[A80Avant]

right, here is a modifed photo from ETKA to which i have erased the AAN configuration to be able to point out the ABY/ADU configuration



On the first picture you can see how the system is configurated. It looks like ALL crankcase ventilation has to go through the pressure regulating valve, as there is no other way for them to escape. The One way valve is located on the metal tube AFTER the pressure regulating valve and NOT on a separate tube.

therefore is the pressure regulating valve is CLOSED, how are the oil vapours reaching the inlet manifold????? (see photo 2)



SO under boost, i agree the pressure regulating valve is OPEN and all vapours are going to the 'maf to turbo hose' and get to the inlet manifold going through the intercooler route.

My question therefore would be, is it possible that this valve is NEVER 100% closed, but it is actually 'regulating' the amount of vapours needed to be circulated through the one way valve or through the maf to turbo hose depending on circomstances?

[UrS4boy]

right, here is a modifed photo from ETKA to which i have erased the AAN configuration to be able to point out the ABY/ADU configuration

On the first picture you can see how the system is configurated. It looks like ALL crankcase ventilation has to go through the pressure regulating valve, as there is no other way for them to escape. The One way valve is located on the metal tube AFTER the pressure regulating valve and NOT on a separate tube.

therefore is the pressure regulating valve is CLOSED, how are the oil vapours reaching the inlet manifold????? (see photo 2)

SO under boost, i agree the pressure regulating valve is OPEN and all vapours are going to the 'maf to turbo hose' and get to the inlet manifold going through the intercooler route.

My question therefore would be, is it possible that this valve is NEVER 100% closed, but it is actually 'regulating' the amount of vapours needed to be circulated through the one way valve or through the maf to turbo hose depending on circomstances?

I think you are right and now I understand what our mutual was all about. I have been looking at the AAN and not the ABY (we don't have any over here). However, I now see the differences and think that the pressure regulating valve MUST be a variable opening, at least for the ABY (and ADU and, I guess, 3B). I have a 3B VAG study guide but it says nothing about the crankcase ventilation system.

I am going to mark up a version of the ABY crankcase ventilation system for your (and others) to comment on.

Sorry for being so AAN-centric.

We'll get it sorted.

[UrS4boy]

Trial ABY Crankcase ventilation diagram

Thanks to A80avant's (Vassili's) persistence, I have *finally* come to see the difference between the AAN and ABY crankcase ventilation systems. I have marked up a diagram to show the ABY situation However, I don't know what the final connection to the ABY/ADY/3B intake manifold looks like. Help appreciated. See attached diagram.

[A80Avant]

Not to worry! im sorry for being uptight about this but it seems that everytime i engage in a conversation regarding the crankcase ventilation system, i can never 100% figure out how it works, so that i mount the tanks/valves/ or any additional things i need accordingly!

Since my rubber gasket is sweaty again, i must dry it out in order to see if the current setup has any meaning or my vent to atmosphere temporary solution is good enough or it may cause more problems instead.

[A80Avant]

the circled thing on the photo, i think is the N80 valve, isnt it?

[UrS4boy]

the circled thing on the photo, i think is the N80 valve, isnt it?

It *does* look like the N80 evaporative emissions valve but that makes no sense there. The N80 is involved and carbon canister vapours do enter the engine but the way the ETKA drawing was done, it should be flow to that device NOT flow from it (based on the orientation of the Item 20 Bleeder valve).

Do you OR anyone have a photo of the 3B/ABY/ADU intake area to show how the crankcase ventilation system connects to the intake manifold (*IF* indeed it does).

Now I am going

[Jamo]

The red ring on the diagram is the output from the block the N80 sits on the t-piece you've got it ringed as what is this

[newsh]

I think the PCV valve gets sucked closed when you shut the throttle, to give a greater vacuum to the crankcase, otherwise most of the vacuum would be applied to the MAF hose.

Any thoughts on this guys? The effect would be different between AAN and the others though, (3B is substantially the same as ABY)

Vas, Its true that the regulating valve is never completely closed, the diaphragm actually has a hole in it.

[UrS4boy]

The red ring on the diagram is the output from the block the N80 sits on the t-piece you've got it ringed as what is this

Sorry, I don't find too much about this as funny. What I need/want to know is whether or not there is a connection to the intake manifold and the crankcase and cam cover ventilation system. I just want to get it (the diagram right).

[Jamo]

? geez yes the N80 is on the tee pipe that goes into the back of the inlet manifold so it can vent fumes to be burnt under combustion, it never sees boost as that's where the 1 way valve is on the ABY

[UrS4boy]

Any thoughts on this guys? The effect would be different between AAN and the others though, (3B is substantially the same as ABY)

Vas, Its true that the regulating valve is never completely closed, the diaphragm actually has a hole in it.

Newsh: And by "PVC" valve, do you mean the bleeder valve? (Item 10 in the AAN diagram and Item 20 in the ABY diagram). The bleeder valve is a ball valve that is opened under vacuum and closed under pressure. Flow should be from the big end (where the ball/cage/seat is) to the small end when under vacuum.

[newsh]

Newsh: And by "PCV" valve, do you mean the bleeder valve? (Item 10 in the AAN diagram and Item 20 in the ABY diagram). The bleeder valve is a ball valve that is opened under vacuum and closed under pressure. Flow should be from the big end (where the ball/cage/seat is) to the small end when under vacuum.

No I mean the regulating valve, the one Vas is saying he doesn't know how it works or why its there. The other one I call the one-way valve, we know what that does, it stops boost getting into the breather system , when mine failed open the cam cover gasket blew out.
The One-Way (or Bleeder) opens when you come off the throttle to suck fumes direct into the engine, at this point I'm wondering if it sucks the regulator valve closed.

[A80Avant]

After clarifying all these aspects in my head, IF every valve and system is operating as it should and you still get the camcover leaking oil residue, what is causing it?

excessive boost? why is the system getting overwhelmed?

When i look at the pressure regulating valve and it's small opening i get the impression that if the excessive oil is coming down through the route at the back of the head and then some of it trying to go back up, could that be causing a bottleneck to the system?

when i alter the route of the system to relieve some of the pressure created on the camcover, i use a T junction from the tube that comes from the back of the head and goes to the block (downwards route) and take the T junction hose directly to the catch tank, thus bypassing both the pressure regulating valve and the one way valve. Unless i clean the rubber gasket and have another look, i cannot be sure if this way it works adequatelly, but i can say that this way the tank gets filled much faster.

If i only connect the tank to the route that goes to the turbo to MAF hose and leave the rest of the system in place, then the tank is near to empty most of the times, and the cam cover gasket is leaking, so my cam cover is still overwhelmed.