Sounds like the turbo coolant hose in the valley has blown, its a small hose which is a common fault on all models after 2013... the Intake manifold, fuel lines etc need to be removed to get at the hose which is only about 50mm long, many choose to use an aftermarket higher quality piece instead of the Mopar rubbish...
Jeep has known about this fault for around 10 years and it seems has done nothing about it..
Any half decent diesel mechanic could do the job but as for Darwin I have no idea who......
All Grand Cherokee in Melbourne do make a replacement hose section which is of better quality than anything Jeep uses...
My Book I have noted the hose required is a silicon hose 3/8" x 100mm with a black fire sleeve with an ID of 19mm and 100mm in length and low profile hose clamps to suit..................
The complete pipe is a Dorman 667-562
https://www.ebay.com.au/itm/15593289...Bk9SR-Lwo5r0Yw
If you look at the ebay link you can see in the pic that the Dorman is a braided hose while the Jeep hose is a old rubber job, most just remove and replace the faulty rubber bit......
Have a read here;
http://www.ausjeepoffroad.com/forum/...=158361&page=8