Very loud rattle on my HDi

[kentiiboii]

I'd say pulley I had same problem.
Best thing to do is run your
Engine and listen inside your cam belt cover by hold a screw driver to the plastic and put it to your ear. Sounds daft but has helped me a lot!

Second I'd do is jack the car up and look at the aux belt from side view. When I had the problem looked at the pulley and you could tell straight away it was that.