[Big hammer]

Heat the plug , Don’t heat the housing! After the vice grips don’t work, try a center punch tapping it in a circular motion in counter clockwise. For those suggesting welding a nut ? Don’t you first weld a washer and then a nut to the washer ?? When I worked in an airline tire and wheel shop sometimes to remove counter sunk screws we would have a welder tig weld 2 towering tits to the screw heads and then used vice grips.