Hum without rattle
There was a nissan advisory somewhere on removing the top & 2nd chain guide for ka24de since they used to wear and cause damage when they broke into pieces and fell further into parts under timing cover.
Here’s a quick diagram on what to get rid of. For that you just remove top valve cover (12 m10 bolts from what I remember) and few more m10/12 bolts to remove top timing cover to get to the 2nd chain tensioner.
Remove the old gasket material and reseal with fresh gasket maker seal (I use the copper type – about $7).