Let's play "how screwed am I?"

Finding the reason why you had coolant in the cylinder is your first issue here. You had a lot in there and then you cranked it, both bad signs. Compression test and/or leak down test are something you should do before tearing it down. Then take the heads off, go over them very carefully (I missed a tiny pit on a 22re head and put it all back in, and had to take it apart a second time...) and take it to a machine shop and have them look it over. You can also check the head gaskets at this point and notice any catastrophic failures.

You seem willing to do this, so there is no reason you can't take a head out and put it back in. My only concern is that from cranking it with liquid in there you really need to do some footwork to make sure the bottom end is solid. If it's not, your best bet is to not waste your time and replace the whole engine.

 

I watched this full series before. Such a great and informative video. Hopefully I will never have to replace a head but I if do Im glad this was made.

 

The oil looks normal.

So when I picked up the truck, the mechanic said that he actually had no idea what caused the problem, that he was going off what I said when he said it was because of weak antifreeze (he seemed to think I told him there was water in it…?). They got it started just by cranking it out, apparently.

So all I really know is that it's blowing tons of antifreeze out the tailpipe. What in the world could have caused this?

 

Sounds like a blown head gasket or a cracked head, but unless someone tests something, you're not going to know.

 

Right; I'm asking what could have caused such a thing.

 

If it never overheated from the low coolant than I guess it just rotted out from inadequate maintainance.

Or it did freeze and break a head.

Since we don't even know what's truly wrong yet it's hard to finger out the reason it happened.

 

Not sure I would trust Haynes as a wheel chock. It wouldn't tell you to "fold in half" and would only state "place in rear of vehicle." Kidding aside, I have used Haynes with success and many WTF moments. The FSM is the way to go.