2013 ISX15 CM2350 EGR Tune & Coolant Leak

[Chamberpains]

Not all coolant leaks look wet or have remnants of the coolant where it's at. Like a coolant leak external on a head gasket will oftentimes look like a rust Line running down the head on the exhaust side because the heat of the exhaust Burns off the coolant as it drips out.
Here's what they commonly look like if the heat around the leak is high enough to evaporate the coolant.