Upgrade... or is it?

[ekam]

So the story on dirty valves with a quick chat with my mechanic who deals with VW/Audi, BMW and Pcars.

- Highly dependent on the type of driving you do. If you don't drive your car hard and get stuck in traffic a lot, that's bad news. The engine needs to heat up to reduce the accumulation.

- BMW is worse than Audi on this matter, so much so they make valve cleaning as part of their regular maintenance schedule.

- 100k km would be a safe number for the service. The mechanic says it can be anywhere from 80-200k km, based on your driving style.

- Forced induction engines don't seem to have dirty valves due to extra heat and airflow.