[Roger24]

Rattle sample I found on youtube that matches

So my sisters' cruze just had this problem after changing the oil and refilling the coolant.
Then it ended up sounding like this video at idle.
Would any happen to know what the deal might be?
Any more elaboration feel free to ask.

 

[JLL]

Is it a diesel? If it's not, and the car didn't sound like that before; something probably is not getting enough oil in the head?

 

[Thebigzeus]

Water pump is going out.