Newbie here and another proud owner of a 406, in my case a 2000 hdi (110), ~70k. I’ve got a few questions, wondering if someone can help.
In the last couple of weeks i’ve noticed an increasingly louder engine noise, especially when idle. It’s kind of hard to explain and maybe someone not familiar with the car wouldn’t notice, but i can say that i always considered it a fairly quiet diesel and now it sounds a bit like an old 1.9d, with a lot of knocking. After sticking my ear to the engine, the knocking seems to be more evident around the cam belt area.
When driving, the engine noise is fairly much the same as it was, except at high revs (~3000/3500), when it seems to get louder (that is, more than would normally before) as if the engine is under severe load (never did 4500rpm

Coincidently (or not), this happens right after i’ve had the crankshaft pulley and rear engine mount changed and was hoping for even a quieter car (although the car doesn’t seem to vibrate more or anything like it, it’s just noisier).
Someone has ideas on this? can it be related? or is something else on its way to go?

Thanks in advance.