Xsara oil pressure light and engine noise

Sounds rough. I had a similar issue with my old Opel Astra, though it was a diesel. Same symptoms: oil light and nasty engine noises. I'm no expert, but have you checked the engine oil level? It might be worth a look before jumping to conclusions.

Yeah, I checked the oil level, and it seems fine. Could it be the oil pressure sensor then? Is it hard to replace? I'm trying to avoid a massive repair bill here...

Could be the sensor, sure. With my Astra, the oil level was fine too, and I hoped it was just the sensor but the noise got worse quickly. Turned out to be the oil pump in the end. Honestly, I wouldn't mess with it too much. Take it to a workshop before you do any further damage.

Okay, I took your advice and brought it to a workshop. You were right, it was the oil pump! The damage was done, costing me 755€, including new bearings just in case! Thanks for the heads up!