Coolant hoses OK but found this
Checked the coolant hoses from engine to DEF unit, all OK. Big thanks to Rustynuts for the drawings. While I was under there, I found this harness pinched between the frame and a cast iron bracket that holds up the front of the DOC(cat). All these wires go to the sensors and electronics on top of the DOC. There was maybe a 1/4" gap, I have no doubt that this would have been a problem in the future. Loosened a few bolts and the inlet clamp and the straps holding the DOC up so I could get a little movement, then moved the harness to where it should be.
I wonder if/how many others are like this?