loose AWX hose

"I found a loose hose in the engine compartment today. The large hose from the air filter box to the turbo has a small connection, about 1.5cm in diameter, just before the turbo. This connection was detached, and there was oil vapor present. The hose goes under the engine cover and seems to be heading in the direction of the EGR valve. Can you tell me if I'm right about the EGR valve, and where the oil vapor is coming from?" MKB: AWX Audi A4. Unfortunately, the hose is not connected to the vacuum hose routing diagram I found here.

Could it be the crankcase ventilation system? The hose doesn't have a clamp; it's just pushed on. And it's not related to the control pneumatics (it's too thick).

benje2 wrote:

Could it be the crankcase ventilation system?

Yep, that's it.

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m;

Thank you, I understand. I usually do it that way anyway, but yesterday it was dark and cold, and I only had a phone with a camera!?
I'm only surprised that you can only tell by the smell of oil, and not by the blue smoke or a false air intake. It was a real coincidence that I saw it.

The boost pressure is still being achieved. If the mass airflow sensor (MAF) reports only a slightly lower value, but the soot limiter still doesn't activate (or only activates minimally), you won't notice anything. If the LMM were also aged (meaning it was already operating close to the soot limit), you would have noticed it.

Why does the crankcase ventilation system sometimes come loose? Is there pressure in the hose? Or could it be a pressure surge from the turbo? Or could it simply be due to vibrations?
"Could something have happened there, even though it seems like nothing is going on? Or are there any potential side effects?"

Nothing happened. The reasons could be, for example, that it wasn't properly connected, that someone forgot something, or that there were vibrations. Take a look at the connections. Don't let him leave again so soon.

Quote:

dark, cold, and I only had a phone with a camera

.

oh, come on

Light helps against darkness (there's also a portable version, called a flashlight).
cold - softie
My phone takes better pictures at night than my digital camera (when I turn off the flash).

You can also do a complete oil change at 3:00 AM (I've done it).

Okay, now I won't bother you anymore, otherwise you might tap me on the shoulder .

greetings
martin