Engine rattle

[euclio]

Hey folks. Just had a rattling sound start today near the serpentine belt/belt tensioner. From what I can tell the sound is coming from this nut, which is square of all things. I can see it wobble and vibrate while revving the engine:

Any idea what this nut is? Anyone else ever have this problem?
1999 w/190K.

[skyline084]

Well if you see it wobble than that's your problem. Looks like one of the bolts that go through the bracket that hold your power steering pump or alternator on.

[euclio]

Well, the thing that really throws me off is that it doesn't appear to be a standard nut. Hard to get a good look at it with the tensioner assembly in the way though...

[skyline084]

Look at what it is attached too. Is that your alternator? It looks like the same bolt that holds my bracket on

[euclio]

FYI, it was a loose alternator bolt, the nut (which is square) of which cannot be tightened from the side near the tensioner assembly. Had to use a long extension and a swivel to get to it to tighten it up from the other, bolt, side.
Thanks,
Jason

[skyline084]

good deal