Possible blown head gasket or worse
I turned mine over when I had it apart by grabbing the fan and pulling on it.
Have you considered that it may not have had coolant in the cylinders? Those exhaust valves look pretty well cooked. When mine burned they didn't even look that bad yet.
Was this motor banging on all 6 cylinders before-hand? I don't mean to insult but did you pull each plug while it was running to see if it ran worse when you took the wire off each one? Mine was banging on 5 cylinders due to a bent pushrod, then started running on 4 (I did not know the pushrod was bent or 1 cylinder down because it ran fine) then one of the exhaust valves burned, and I assumed the gasket cracked. I popped the head and found some clogged coolant passages, and bad valve (the one that quit working) but then it could work it's way past the rings anyway, so it may not be visible.
The way I checked if mine was leaking was spraying a bunch of wd40 on the head upside down and seeing if it leaked past anything. Sure enough it leaked past a few exhaust valves and I had the head rebuilt for $270 - new valves, everything.
When you turn it over if the motor is not too dry, coolant will shoot out of that hole in the back left. I found that out the stupid way... and had to clean it all up.
That wd-40 thing an old mechanic guy suggested to me. Pretty easy to tell what's leaking that way. You can see my exhaust valves were just as white, and there was no coolant in the rest of the block.
I turned mine over when I had it apart by grabbing the fan and pulling on it.
Have you considered that it may not have had coolant in the cylinders? Those exhaust valves look pretty well cooked. When mine burned they didn't even look that bad yet.
Was this motor banging on all 6 cylinders before-hand? I don't mean to insult but did you pull each plug while it was running to see if it ran worse when you took the wire off each one? Mine was banging on 5 cylinders due to a bent pushrod, then started running on 4 (I did not know the pushrod was bent or 1 cylinder down because it ran fine) then one of the exhaust valves burned, and I assumed the gasket cracked. I popped the head and found some clogged coolant passages, and bad valve (the one that quit working) but then it could work it's way past the rings anyway, so it may not be visible.
The way I checked if mine was leaking was spraying a bunch of wd40 on the head upside down and seeing if it leaked past anything. Sure enough it leaked past a few exhaust valves and I had the head rebuilt for $270 - new valves, everything.
When you turn it over if the motor is not too dry, coolant will shoot out of that hole in the back left. I found that out the stupid way... and had to clean it all up.
That wd-40 thing an old mechanic guy suggested to me. Pretty easy to tell what's leaking that way. You can see my exhaust valves were just as white, and there was no coolant in the rest of the block.