I'm hoping the Cu is just break-in material from thrust bearings, lifter rollers, and oil cooler being new and not from things coming apart. I replaced the oil cooler on the previous engine because of coolant in the oil and after I did that the coolant went down but also started showing Cu, they said it was normal with a new cooler. I haven't looked through all the paperwork yet to see if I got a new reman oil cooler with this engine or if they used the one from my previous engine. Either one could cause Cu to show since the one I replaced was put in service not long ago.
Most of the work I do myself, but this was too big of a job for me. They took the front cover off because it was leaking and had to take the head off to find out if the lifters came apart. Then they pulled the camshaft and saw that it was trash and recommended new cam bearings too. When I decided that a reman long block was the best route they had to reassemble my engine to send it in as a core. At the time, I needed it done so I could put her back to work. I replaced the oil cooler, thrust bearings, resealed the oil pan, replaced the front main seal, and adjusted the valve lash, set the injector height, and adjusted the jakes myself with guidance from a friend. I also replaced all the shocks on the truck, replaced the input seal on the power divider, resealed the rear drive axle carrier to the axle housing, replaced both drive axle torque rods, and a few other things in the past few weeks. I've had a lot of time on my hands recently with freight rates so low right now. I have a few more projects to get done yet, I'm guessing I'll have plenty of time though since rates seem to be staying down.
She is a pretty cool truck though. A darn tough work horse.