What are the 2 hoses that connect to the pass air intake hose?

A6 All/ S6 All
#1

I’m going crazy chasing down the cause for my misfires on idle. Now I’m checking the 2 breather hoses that connect to the pass/right air intake hose. Can someone tell me what they do?

The upper breather hose seems to be PN 07L133750F (Suction jet pump with hose, https://www.oemvwshop.com/07l133750f-suction-jet-pump-with-hose-p528583).

I think the bottom one with the square squeeze-tab is #2 in the diagram below. Does it one-way vent air into the crankcase?

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The square-squeeze tab has broken off and I’m currently running a set of zip ties to secure to the air intake hose. Could that be causing my misfires on idle? I don’t hear any hiss from the connection at idle.

How do I check if these hoses are working properly?

#2

One of those hoses is the crank case vent so it connects the intake hose to that location shown in the v. The other one wraps around and I believe is used for the vacuum brake booster air feed line. Someone correct me if I am wrong?

#3

Let me add that the hose pictured above has a spring check valve in it. When I replaced, the new hose had a different operating pressure than the oem one I replaced in my car, starting in my opinion it needed replacement.

Some notes about it here also on Sept 21st

I think we have learned that if we replace the oil seperator and all the pvc hoses we have the best chance at the car idiling correctly. These v10s like a perfect pvc system…

#4

I did check the crankcase vent hose—the check valve was correctly blocking any airflow out of the crankcase. I could blow into it, but I don’t know if the spring rate is correct.

Is there a list of all the PCV hoses that need to be inspected/replaced?

#5

It is really only those hoses that you referenced. That one that goes to the v, the oil separator, and the large hose that spans the two heads and connects to the oil separator. Also all the vacuum lines. While you are doing all of this you’ll have to remove the IM, so replace the check valved oil seperator drain hose (or clean it like I did) as well if you havnt done so replace the figure 8 oil filter housing oring and sandwich plate gasket in the v.

I feel I am forgetting something hopefully someone else chimes in but I think that’s it man.

#6

Is there any point to building a DIY smoke machine and pumping smoke into the PCV hoses to search for leaks?

#7

Yes or buying one I def would own one. Wish I did lol would prolly have saved me some swear words over the years haha.

#8

Yeah. I called all over to find a garage that can smoke test around here and no one knew what I was talking about (Brussels using google translate French) Finally found a Bosch auto shop that said yes—but all they did was scan the codes with Bosch software and announce that the ECU2 must be bad because there were so many misfires. I tried to challenge them, but it was hopeless over google translate. I think in the back and forth that they were thinking oil leak and didn’t understand “PCV”.

I feel like a chump and paid 50€ for the privilege. So I guess I’m making a smoke machine this weekend.

What is the procedure? Do I just pump smoke into that same one-way crankcase vent hose and look for smoke coming out?

#9

Yes your goal is to pump smoke into the intake / intake manifold and see if you can catch where smoke is escaping the engine. You do not want to see any smoke anywhere in the engine bay.

I have never done it myself so maybe grab a youtube video of someone doing it properly or wait for a better reply here. Sorry I’m not of more help my friend

#10

I made one a few months back

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based on what this guy did


https://www.youtube.com/watch?v=tixozqgSwN0

I disconnected the intake hoses from the airboxes and stretched nitrile gloves over them to allow the system to pressurize. I then fed the smoke in through the hose connection on the very front of the intake.

Here is a short video showing the result

#11

Thanks so much–this was exactly what I needed. After weeks of guesswork and trying to find a garage to do a smoke test, I finally went out and built a smoke machine. Adapted from the video you shared above.

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Found a leak at both Bank 1/2 Throttle Bodies at the gasket to the Y-pipe.

Why the random codes/misfires–what is the cause?
S6 V10 Misfires on Cylinder 6 only on coldstarts and really random. DESPERATELY NEED HELP!
S6 V10 Misfires on Cylinder 6 only on coldstarts and really random. DESPERATELY NEED HELP!
#12

That’s a nasty leak.