Formsand in der Ladeluftstrecke? | Posts 16+

matthiasTDI96 wrote:

... I have to disagree with Bertil on that point. ....

Where are you disagreeing with me?
I don't see anything there... At least, not regarding the casting process and the foundries.

Quote:

... You should see what the intake air paths look like in vehicles that use dry cotton filters (sport air filters). You'll find a kind of "grinding paste" buildup in the quieter areas (hose connections, intercooler, etc.). Surprisingly, these engines often last well over 100,000 kilometers. ...

My AXR has almost 250k miles... with a K&N filter since 15k miles... the turbo is original, the MAF sensor is original... but the clutch is the fifth one!

ulf wrote:

... My "worst-case scenario" thoughts also go in the direction of debris clogging valve sealing surfaces: If a valve doesn't close properly because of this, AFAIK hot exhaust gases can leak past and cause it to warp... or am I wrong about that?

You'll need a bit more than just a few crumbs.

Quote:

You'll need something more than just a few crumbs...

The crumbs will definitely be ejected at the latest during the next gas change.

"I used to have more problems with crumbs in older (T)DIs, specifically related to issues with the intake manifold design. I would clear the channels by scraping and blowing them out without removing the catalytic converter, and only when the intake valve was closed."
During the subsequent test drive, the engines occasionally sputtered slightly if a small piece of debris remained lodged between the valve and its seat.
Once the engine had warmed up after a few kilometers, it ran perfectly smoothly.

After that, the vehicles have generally run without problems, with some exceeding 100,000 km, and I am not aware of any engine-related failures.

ulf wrote:

My GAU (Worst-Case Scenario) thoughts also go in the direction of stuck crumbs in valve sealing surfaces: If a valve doesn't close properly because of this, AFAIK glowing exhaust gases can leak past and cause it to warp... or am I wrong about that?

Well, you could also get struck by lightning while you're taking a dump.

But perhaps that's the key that Autobild was waiting for: The reason for the high oil consumption in various TSI engines is due to casting defects in the turbocharger manufacturers, who were pushed to their limits... Sand -> Defects -> Oil leakage