Maxforce, what does this black spot around the head gasket mean?

Oil getting by the gasket? Looks like it got to the coolant galley. Did you take an oil sample? Is there any coolant in the oil?

 

Combustion was getting by there. That's why it was getting hot. The cracks in the head could have been caused for several reasons. Some are very prone to cracking, especially when overheated.

 

MLC Adventures has got it right, I think. The cracks in the head, and super high pressure from compression indicate that. I should have thought of that. But that's why I drive and am not a mechanic.

 

What's your history with this teuck?

 

So is the head and coolant ports being blocked off a new thing? What are you talking about.
Heads normally crack from being run hot. Head gaskets can leak at the compression ring from being ran hot and other reasons.
For what ever reason combustion ( air ) gets into the the cooling system that will make it run hot. The pump is a liquid pump. A small amount of air will make it cavitate. Then it will no longer move liquid.
What was the original problem? This is an old chicken and an egg question. Did the chicken come before the egg and no one knows.
If the thermostat or radiator went bad they could cause the coolant to boil. It then has air in the system and will not cool.
But no one ever saw it hot on the gauge. Coolant sensors were made to read in liquid. If the operator is not paying attention the system can get air in it and the gauge lies because it is not in fully in liquid.
Yes engine shut down systems and such should catch this and shut them down. I have seen some not work so well.