Oil prime

[PureHybrid]

I'm with Jason. To me the heat marks on the failed area just look like heat from friction after it cracked, it's fairly local

If I break out a torch for a stubborn bolts it's not for 20sec, more like 2min

 

[Chevy1925]

If it was friction, why doesn’t any part of the center section show the same thing? Its clearly seen far more friction

 

[2004LB7]

I'm not saying it's from friction. But definitely not from a torch. I wonder what the backside looks like