Skoda Octavia Diesel Oil Pressure Issues

Low oil pressure is never a good sign, especially with those noises. First, check the engine oil level and condition. Is it at the correct level? Does it look sludgy or thin, or smell burnt? Also, what oil viscosity are you using? If it's too thin, especially in an older diesel, it might not be providing enough lubrication. Have you checked the oil pressure sensor? Though, with the noises, I suspect it's more than just a faulty sensor.

The oil level is fine, and I changed the engine oil recently, so it's relatively new. I used the oil viscosity recommended in the car's manual. How can I check the oil pressure sensor? Is that something I can do myself without special tools?

If the oil level and viscosity are correct, and you're still getting the low oil pressure warning and noises, it pretty much points to a failing oil pump. The oil pressure sensor could be faulty, but the noises suggest the engine isn't getting enough lubrication. Checking the sensor usually involves using a multimeter, but given the symptoms, I wouldn't drive it any further. You risk doing serious engine damage. I'd recommend getting it towed to a workshop to have the oil pump checked and replaced. It's better to be safe than sorry.

Just to let you know, you were right. The workshop confirmed it was the oil pump. The total cost was 755€, but the car is running well now. Thanks for the assistance.