EGR Problems on 2016 Prostar

Hey guys!
I’ve had my truck for over 3months now with absolutely no problems whatsoever, until recently. Out of nowhere it sort of derated to 60mph and the rpms weren’t going anywhere beyond 1300! Took it to Rush Truck Center in ATL and they diagnosed it as a failed EGR Valve. 3days and $2800 later, it was fixed and everything was back to normal....at least for 20hours! I woke up and found a flowing river, courtesy of my coolant and it was dripping like it came straight from a Tap! Looked like it was leaking from around the motor area. Took it back to Rush, and before I even got there, the leakage had ceased! Some technician looked at it but couldn’t seem to find anything wrong, after pumping into the coolant tank(excuse my layman terms, I’m still a new O/O)
So, their conclusion was, “the new EGR valve is working as it should be, so, the rest of the fittings on the EGR Coolant can’t handle the flow. Long story short, now I apparently need a new EGR cooler, and a bunch of other things that might set me behind another $5-6k!
The leak hasn’t happened again but I’m driving on egg shells right now! Can anyone kindly make me understand what could be happening?
The engine is a NAVISTAR N13, last 6 of Vin#201329.
Thanks in advance Truckers!

 

Thank you for your reply Heavyd! I truly appreciate! Those were my thoughts exactly but they weren’t willing to take a closer look at loose hoses or something like that. The only way The would do that was to have me leave the truck for a few days so they can do a new diagnosis. My coolant hasn’t leaked again, although my truck has been running all day. I don’t know the coolant leaks after the engine is shut down for a while or something.