I got a call from the mechanic today, and it appears that my number two piston is cracked. He said he didn't think that's what caused the overheating, but he seemed relatively certain that's why I was getting the CELs.
They're planning to replace the cracked piston. This is all covered under the 30-day CarMax warranty, so I don't have to worry about paying anything out of pocket. What I'm wondering now, though, is what else I should be concerned about given that I have been driving around with a cracked piston.
Given that they'll have my car in the shop for about a week while they wait for parts, is there anything else I should have them take a look at while they've got things torn apart?
My main concern is about anything that may have gotten damaged while it was overheating, and what caused the thing to overheat in the first place since the mechanic doesn't think the cracked piston caused that. He suggested that the overheating could have been caused by the CarMax folks not hooking something back up correctly when I brought it in after the first CEL.
Any help you all can offer is greatly appreciated.