A lot of X and P series owners like me have complained about rattle noise during fast prints and heavy vibration. If you haven't looked at the part cooling fan in the hot end cover yet, check and see if the screws that hold the fan in are loose. I've noticed that even though they might be screwed down the entire way, they could be bottomed out before they actually tighten the fan in place causing the rattle sometimes.

Remedy I found was using some sort of washer or Oring to fill that gap so I created this small washer to perform that duty for anyone who may run in to this issue and not have tiny washes laying around. I think assembly is self explanatory from the pictures, just put em on the screws and reinsert.

This wont fix a rattle issues coming from somewhere else, but if you suspect the fan, its a 2 minute print and very little work to be sure. It should also go without saying to use something higher temp resistant like PETG/ABS…etc