Probably overheated on that part. Remove the termostat for now as well and flush whole cooling system a lot of times. There's oil everywhere.
cleaning attachment for power drill.Can you tell me what is the most effective way of cleaning the face of both the head & block
Something like this https://i.ebayimg.com/images/g/hK8AAOSw ... s-l300.jpg
Usually it's done by flat tool that doesn't score stuff. https://i.ebayimg.com/images/g/8XEAAOSw ... s-l300.jpg
But you need to grind down the edges.