Turbocharger Failure? Galaxy 1998 TDI AFN

Six weeks ago, I replaced the injectors and glow plugs on my Galaxy (1998, TDI, AFN, 81 kW, 302,000 km), and during that process, I also replaced the intake pipe from the mass airflow sensor (MAF) to the turbocharger (it was broken and had a crack/hole). After that, the turbocharger consumed 1 liter of oil over a distance of 800 km. The oil consumption before that was 0.5 liters per 5,000 km.

Here's what I did or checked:
Replaced the air filter (50,000 km, it was completely clogged).
2. Checked the engine ventilation system at idle (almost no pressure and venting, the hose was almost dry inside).
3. Checked the intake manifold after the turbocharger (it's quite oily).
4. The intake manifold was removed in front of the turbocharger, and the play and smoothness of the turbine were checked. Result: virtually no axial or radial play; the turbine is difficult to turn with two fingers through the narrow opening. Play was checked with a small pair of pliers on the nut.
5. Tested the VTG (variable geometry turbine) with hose and vacuum. Result: Operates smoothly, travel distance approximately 1-1.5 cm.
5. Acceleration log recorded. Result: No changes in the boost pressure curve compared to a log from one year ago. A brief overshoot followed by a short drop at 2,500 RPM. The duty cycle briefly increases to 70%, then drops to approximately 55% at 4,000 RPM. Otherwise, the boost pressure is 1,948 mbar. No turbo whistle is audible.

"I'm only driving carefully and short distances now. I have the impression that no more oil is leaking. The car smelled for a while, but I don't notice it anymore."

Okay, here are my questions:
a. Could it be that the vacuum in the suction line has drawn the oil out of the charger seal?
b. Does a relatively tight loading wave indicate a problem? It should normally have up to 1 mm of play and run smoothly.
c. Is there an HSJ filter located behind the loader? Does it get clogged with oil sludge and then burn it off?
d. Vor dem Ladertausch schrecke ich wegen unklarem Befund, der Arbeit, Komplikationen (abgedrehte Stehbolzen, etc.), den Kosten, usw zurück. Das Auto ist rostmäßig noch für 2-4 Jahre gut (1,5 Jahre TÜV). Der Rest ist o.k. Hatte eigentlich (evtl. etwas voreilig) die 350.000 km ausgerufen. Trotzdem stellt sich die Frage der Wirtschaftlichkeit. Bräuchte auch noch ein Auflastungsgutachten für 400 € wegen gelber Plakette. Was würWhat are you doing?

Thank you in advance.
Richard.

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After that, the turbo engine consumed 1 liter of oil for every 800 kilometers. Oil consumption before: 0.5 liters per 5,000 kilometers.

Why do you think it's related to the timing chain? The problem could also be caused by the engine itself.

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replaced the air filter (50,000 km, it was completely clogged)

Was the oil consumption then lower?

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I checked the engine ventilation system at idle (almost no pressure and it was blowing air out, the hose was almost dry inside)

. That's strange. I would check the crankcase ventilation valve and the pressure regulator valve. Perhaps the high oil consumption is caused by a problem there?

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...The play and ease of rotation of the turbine were checked. Result: there is virtually no axial or radial play; the turbine is difficult to rotate through the narrow hole with just two fingers.

The turbine wheel should rotate easily/smoothly with a pen or finger.

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...Is a relatively tight loading wave a bad sign? It should normally have up to 1 mm of play and run smoothly.

If there's 1 mm of play, then in my opinion, the bearing and therefore the TL (presumably referring to a specific component) are lost.

After the sudden increase in oil consumption following the repair, I would first investigate that. Something might have gone wrong. Take a closer look at the crankcase ventilation system first. It seems like the turbocharger is still working.
hg
Herbert.

Herbert wrote:

Quote: ...Is a relatively tight loading wave a bad sign? It should normally have up to 1 mm of play and run smoothly. If there is 1 mm of play, then in my opinion, the bearing and thus the TL (thrust load) is lost.

Here, one must distinguish between tilting play and axial play:
"A slight play of approximately 1 mm can be felt in the compressor wheel shaft nut, and this is sometimes observed even in new chargers, without them failing prematurely."
The loader is only defective when the shaft can be tilted to the point where something rubs when rotated, or when the shaft has noticeable axial play.