Head gasket went at somewhere around 164K miles. I had lent it to a friend, and she's not a car person. She went out to start it and it started clanking, then white smoke. She said she smelled "a sweet smell" a couple days before, which was obviously coolant going through the exhaust. I wasn't aware that the 4.2Ls had a known issue with that until I started researching. I trailered it home and dumped it in the barn. It's an otherwise solid truck with no rust, so a few hundred bucks and some labor would be worth it. If I have to put more than about $500 into it, I'll just take it to the scrap yard.