Just picked up a Mini this weekend and I'm not sure if this noise is normal. I didn't hear it at all during the test drive or the 1hr ride home either. I only noticed it yesterday when I took it for a spin. Only at start up and it would come and go when stopped. I can hear it inside and outside but I don't think it's coming from the motor itself. It is a bit louder underneath but I don't think it's coming from the lower end of the motor. I had an old Wrangler with piston slap and it was much louder than this. All fluids are good and at proper levels. No engine lights on. No loss of power through the gears. Checked the timing chain side and that sounds fine. Tried to find similar videos with a similar sound but I didn't find anything yet so I thought I'd ask here.

My thoughts are:
Possibly the SC?
Water pump?
It does have an exhaust leak so maybe it's from the leak and causing some metal connections to rattle a bit.

Posting a video. Hopefully it helps. Kind of bummed if it's something major as the test drive I heard nothing. Murphys law that I don't hear it until after I get it home :/

Video of the sound. Hopefully it comes through clear.


Forgot to add: it's an 04 with 154k

 

So I took my kids to see Sonic 2, came home, fired it back up and noise was gone Took it around the block and still no noise. Took it on a lightly spirited drive and no noise. Weird. I have a feeling a lifter is getting a little stuck. Previous owner did say it sat for a bit. About 6 months. Not driving until i change up the oil and maybe add a little bit of Lucas oil, drive for about 1k miles and do another change.

 

Hopefully, as you allude, the sound won't come back. When you get around to changing spark plugs, perform a compression test so you'll have a benchmark for the future.

 

The stock DMF can sometimes make noises like this - it is normal.
And like you describe, some days it's there and other days it isn't (at least in my experience).
Does the noise change or go away when you push in the clutch?

 

Thankfully no. I thought it might be that but it happens clutch in or out.

Edit: so I just YouTubed the dmf sound and it's almost identical. I'll test the clutch pedal again next time I hear it.