The thick rust color could be from somebody adding a stop leak to the cooling system.
The obvious possible leak sources are radiator, heater core, water pump and Cylinder head.
Check your Oil for coolant or white foam.
If you lost so much coolant the engine overheated and you cant see fluid on the floor or in the passenger foot well I would be very concerned that this is the head gasket.
2003 Pathfinder from 2004 SE 4WD
1997 SER 5sp Manual from new Rear Ended 2009 !!
Gone to the Knacker yard...
New ride 3.0 manual RWD not a Nissan !!!
1997 Sentra GXE from new .... Sold 2008
2001 Sunny N16 RHD from new (N16 Nissan Bluebird Sylphy) Sold