Check your coolant

[Neophyte]

A few pictures I took of a neighbor's tractor engine. He needed help "diagnosing" why his tractor wouldn't start, so helped him figure it out: ran it our out of coolant, and kept running until this happened:



Yes, that's molten aluminum on the sleeve walls.

Check your coolant.

 

[Neophyte]

A picture of the head showing the burn marks