T5 CFCA Endoscopy Cylinder - notable deposition

Good evening, everyone.

"Until now, I've only been an interested reader, but I'm looking forward to getting feedback from experts on the recordings I've made."

It's about a T5 CFCA model, manufactured in 2015, with 184,000 kilometers on the odometer. Cylinder 1 exhibits two raised, light-colored deposits located near the edge of the piston and almost directly opposite each other.

My suspicions range from sealant paste to melting of the piston material due to localized overheating (possibly a faulty injector?). VCDS test drive: No anomalies detected in fuel injection quantity deviation, and otherwise the car drives normally.

Of all the injectors, cylinder 3 delivered the absolute maximum at +0.97 mg/stroke, while cylinder 4 delivered the absolute minimum at -0.65 mg/stroke.

I'll probably do a back pressure test in the next few days; hopefully, that will reveal something.

Has anyone seen this before and have any ideas?

Best regards,

Good morning.

The CFCA engine is known for a problem where, due to high temperatures in the area of the EGR cooler, material degradation occurs, leading to a situation where the component essentially self-destructs.

To me, the marks look like melted aluminum.

Please take a closer look at the AGR cooler.

Best regards,

Michael.

Hi Michael, Good morning,

I had forgotten that.

The AGR Version D was installed at a mileage of 70,000 kilometers. Overall, the cylinder walls look good considering the mileage, with a nice cross-hatch pattern all around. Wear marks are only visible in the area near top dead center, and even these I consider acceptable for the mileage.

Oil consumption has not been an issue so far.

I believe that molten aluminum could be a way, as I mentioned before, to potentially melt the piston.

Or could it be parts from the turbo? "At lower speeds, up to approximately 1300-1400 RPM, the engine feels a bit sluggish. However, a VCDS test drive shows that the turbocharger pressure (target vs. actual) appears normal, and there are no error codes related to turbocharger pressure in the engine control unit (ECU)."

Best regards,
Joe.

Schnurrbartjoe wrote:

Or could it be parts from the turbo?

If a turbocharger starts ejecting parts, it will usually not last long due to the resulting imbalance. Therefore, I would follow Michael's advice, even though the AGR cooler has already been replaced.

Is there any known background information about the engine? Is the car still with its original owner?
The first image looks to me like there might be a scratch or something similar next to the deposits. But I can't imagine how it could have gotten there without the engine needing to be opened afterwards...