Possible timing chain noise?

[klturi421]

For the past week and a half I have been borrowing my brothers 98 explorer. It has ~250K put on it. I believe it is a 4.0L SOHC.

About a week ago I noticed a ticking sound coming from the engine bay and really noticed it when I was at the drive-thru earlier today.

Here's the video with the sound:
http://youtu.be/CImNe4iViF4

From what I have been reading it sounds like it could be either the timing chain tensioner(s) and/or cassette(s).

Any ideas?

 

[2000StreetRod]

Exhaust manifold leak?

I'm not good with identifying sounds on a video but to me that doesn't sound like the normal timing chain rattle from a broken cassette. I suggest checking for an exhaust manifold leak.