Well, I guess I found the mileage limit of German Castrol 0w-30 in this engine. Interestingly enough, it's right around 10k miles, and that's the recommended change by Audi/VW.
The turbo was replaced due to a stuck open wastegate, during this OCI (oil changed at the same time as turbo replacement), so SOME of the iron could have been from that, still fuel dilution got too high. Direct injection has that effect.
The turbo was replaced due to a stuck open wastegate, during this OCI (oil changed at the same time as turbo replacement), so SOME of the iron could have been from that, still fuel dilution got too high. Direct injection has that effect.