Terrible Clattering Noise Coming From Engine - 03 4.0L V6

[PotatoExplorer]

Hey guys, I'm hoping someone could ID this noise for me and at least get me researching in the right direction. It's a 2003 Ford Ranger XLT 4.0L V6 4x4. Here's the link to the video I recorded today (put it on my Flickr account):

Anyone have any ideas? I'd guess it's a broken valve spring? I have no clue how to even begin changing one if this is the case. Anyone have any pointers? I'd like to take it to a shop in town (probably about a mile or two away), but I'm going to take a wild guess and I probably shouldn't be driving the truck anymore...

This of course happens literally hours after I replaced the speedo/odometer portion of my instrument cluster so it would pass state inspection next week

Last night I drove it around town fine for about 30-45 minutes and it was completely fine. I get about 2 blocks away and it started to make this sound. I was feeling pretty crappy so when I got home I just went in to go to bed. Today I start it up (hoping I was just imagining this sound) and this is what it sounded like. Yikes.

 

[RangerX]

Timing belt tensioners? I'm assuming it's an sohc, not an ohv.

 

[PotatoExplorer]

Thanks for the reply RangerX,

Yeah, SOHC, and I thought tensioners at first. I believe the rear tensioners on these are more towards the passenger side and this was definitely coming from the driver side bank towards the rear.

Anyone know of a walkthrough on how to remove a valve cover?

 

[PotatoExplorer]

Timing belt tensioners? I'm assuming it's an sohc, not an ohv.

Well, apparently I don't know what I'm talking about. Managed to pull the driver side valve cover this afternoon. A little labor intensive but pretty straight forward. Here's what I found...

It looks like either the guide or tension took a dump causing the chain to flap around. Looks like it chewed up the top of the valve cover in the process. I'm surprised it didn't jump time and blow the engine. I still wasn't sure if this was my sound so I compared to another video and sure enough it sounded spot on -

Looks like this can be upwards of $2,000 to fix. With the rusting on the rockers, bed back corners, and some components underneath, I'm not even sure if it will pass inspection. I guess I'll be stripping what I can and offloading it to the highest seller

 

[RangerX]

Bummer! I don't really know anything about that engine other than seeing all the threads here about tensioners failing. Seems like the fatal design flaw in an otherwise great engine.
My neighbor just repaired the same issue on his son's Ranger, in his driveway and without the supposedly required special tools, so it can be done...