Recently my '03 KJ 2.8 CRD went through a timing belt/water pump replacement. Accessory drive belt + tensioner were replaced as well.

Did a 300+ miles trip (highway + mountain road). No issues were noticed. Engine working well.

However while parking at the end of the day, became aware of a strange noise coming from the engine bay. Here is how it sounded while idling.

https://www.youtube.com/watch?v=_COTs31w5ek

As it was too dark, I left further investigation for the next morning. However on the next day everything seemed just normal
Let the engine warm up but no sign of the above noise

https://www.youtube.com/watch?v=_wJN7T4iLxg

Any ideas?

Problem solved.

The bolts that hold the power steering pump pulley had not been properly tightened and were somewhat loose.

Beats me why the issue was not evident when idling after a cold start, but the noise appeared after driving for some time.

Bolts were tightened, the noise has gone.

Thanks for letting us know and glad it was benign. Bolts were probably snug and then once warmed up they were loose enough to allow the rattle.

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2005 Liberty CRD. New rockers, exhaust valves; Provent, EGR block & butterfly delete & V6 air box at 100K

1998 XJ 4.0L, 2" lift

First Jeep: 1962 Willys CJ-3B