At low RPM, which occurs in 3 different scenarios (starting, shut down, and clutch-out), the noise I am hearing comes from the engine compartment.
The van in question is a 2003 Kia Pregio diesel van. Here's a link to the video: https://www.youtube.com/watch?v=RhQ9Z10VYTM&feature=youtu.be
In the video you can hear the sound in question right after attempts to start. This sound disappears during idle and in normal driving conditions, but re-appears whenever I let the clutch out enough that the RPMs dip below idle, and it also happens when I shut the car down.
In case you are wondering, there is also a problem with the engine starter-circuit which is cause for multiple attempts to start in the video--I'm still working on diagnosing this one, which I have posted a question for, here: 2003 Kia Pregio Diesel Van: engine starter problem (video included)
I don't really know what this is - maybe knocking from timing being off? Please help :)