Ditto the comments above. As I was reading the original post...the same questions came to mind.
See the image below as to the location of the engine coolant fill pipe (on a 2013 the coolant reservoir isn't visible because it's located in the front fender area)...and you know that it's full when you stick something down into the fill pipe and the fluid level is 4"-6" below the top of the fill pipe's neck.
The turbos and engine CPUs have a "charge air cooler" system that is easy to get confused or conflated with the engine coolant system since it is not really described well in the owners manual...along with it being "front & center" with writing on the lid (versus the engine coolant lid tucked at the back of the engine bay with an almost blank lid).
In the diagram below...
#5 &
#6 is the lid and filler pipe for the engine coolant...and
#1 is the reservoir for the engine coolant if you have the N63TU.
