Peugeot 406 Oil Pressure Warning

Sounds like you might be right about the maintenance. That sludge could be cooked oil and byproducts from blow-by. Has it been a while since your last oil change? Also, did you check your coolant? Head gasket leak could also cause oil contamination, but you'd usually see other symptoms too. And definitely pull the oil filter to see what's trapped in there. Give us the oil color and consistency deets!

Yeah, it's been longer than I care to admit since the last oil change, life got in the way. Coolant level is fine, no milky residue that would scream head gasket. The oil filter, good call! What exactly should I be looking for in the filter? Like, beyond just "dirty"?

Okay, overdue oil change is almost certainly the culprit, especially since the coolant is clean. The filter will be full of the same gunk you're seeing in the oil, possibly even metal particles if things are getting really bad. Honestly, at this point, you're best off getting a full oil change and filter replacement done ASAP. If the warning lights persist after that, then worry about more serious issues. But yeah, get it to a workshop!

I figured as much but needed a kick in the pants. Dropped it off at the shop this morning. Turns out, severely overdue oil change was indeed the big issue. They flushed the engine, new oil, new filter. 165€ and she's purring like a kitten again. Lesson learned: don't neglect the oil changes!