This picture illustrates why good maintenance records are nice.
We bought a 2004 Excursion with the 6.0L in 2014 with 145k miles on it. 2 weeks into it, we had an injector blow up. When the dealership got that fixed, they test drove it and while driving it, lost the FICM, cam position sensor and crank position sensor and had to have it towed back to the dealership for repairs. While driving it home, the engine started running very, very poorly, so we had it towed back in. The wrong injector was put into the engine and essentially blew up. Got that fixed.
In December of 2015 it quit running while we were on the road, no acceleration and then died and wouldn't start. Had it towed to the dealership and was told the high pressure oil pump wasn't working, and that was going to be $2400 to fix. Since they were going to be really digging into the motor to fix it, I asked for a quote to replace the EGR and oil cooler. $3700.
I called a local diesel shop and got a quote of $3200 for all that work and so had it towed there. They called after they looked at it and said it wasn't the high pressure pump, it was the low pressure pump, and that could end up being much, much cheaper, did they have permission to dig into that? Gave them permission and they called back and said "Uh, we aren't going any further until you come down and talk to us and look at what we're seeing." Ended up they found some significant wear and damage inside the low pressure pump, with a chunk of metal they couldn't explain, jammed into it. Our options at that point were a new crate motor from Ford, with installation, for about $18k or a new block, with installation for about $15k or they could try and rebuild it for about $11-12k. They said "try" because without tearing into the engine and knowing how much other damage was done inside, they weren't overly confident of how good of shape the rest of the engine was in. We took a couple weeks to decide because this money was coming out of our house-building fund.
Apparently, they got bored while waiting for us to decide, and disassembled the entire engine, free of charge. They found no other damage inside the engine, other than a valve cover that had been siliconed on because a bolt had broken off, and under that valve cover was the bolt in the picture. It looks like someone stripped the Allen head out, and then used a chisel to knock the bolt loose, and the chunk of metal in the low pressure pump appeared to match the metal from that oil stand pipe bolt.
With the deletes, tuner, upgraded parts and head studs, we were out $12k. We then had to spend another $3500 on front end work, but that is to be expected in a diesel rig with 194k miles on it. Hopefully, we will have a few years before the tranny dies.