Timing belt failure? And did it actually go boom?
We don't know yet. Ed's going to take a look when we get it home. Seems to be that the engine blew a hole in itself rather rapidly, spewed out all its oil and then seized. The oil pressure light never came on, so it was something traumatic.
Not quite a boom, maybe more of a loud clunk or the rattle just getting louder and louder and louder and then abruptly stopping. Boom would have been more impressive!
I'm guessing, broken connecting rod, which then puched through the oil pan, or engine block?
The actual failure was in the rod bearing on cylinder 2. Totally toast with lots of bearing material thrown everywhere. Root cause of sudden loss of oil seems to be a stripped oil pan plug that the shop tried to seal with RTV. I think that was working for a while, but vibrated itself loose causing all the oil to quickly disappear leading to the bearing failure.
I bad a bar on the crank pulley last night and could only get it to turn part way and it would stop hard, which was really leading me to believe it had thrown a rod. This morning with some more force I got it to turn all the way over, but was still surprised when I dropped the pan and found no massive carnage like I expected.