Peugeot 206 Oil Sludge Warning Lights

I had a similar scare with my 206, though I can't recall the exact year. That oil sludge sounds ominous. What color is the oil? Have you noticed any oil leaks anywhere? When was your last oil change? Definitely sounds like more than just a top-up issue.

The oil is really dark brown, almost black, and thick. I haven't spotted any obvious leaks, but I haven't really been looking closely under the car. The last oil change? Uh... that might be the problem. It was definitely longer ago than it should have been. Think it's just oil sludge, or could it be something worse?

Dark, sludgy oil is never a good sign, especially if it's been a while since your last oil change. It points to a serious contamination. I'd bet exceeding the service interval is the root cause of your issues. Given the symptoms and your description, it's best to take it to a workshop ASAP before you do any further damage. I ended up having to replace the entire valve train on an old project car because I let oil sludge accumulate. Not fun, nor cheap.

I feared as much. I took your advice and went to the garage. Turns out, the oil was indeed heavily contaminated because I missed the oil change. They flushed the engine and changed the oil and filter. Cost me 165€, but seems to have solved the problem. Warning lights are gone. Lesson learned: stick to the maintenance schedule!