I just changed out the coolant in our 7500. followed the instructions on rvgeeks.com video.. put coolant in recovery tank to mimimum cool level.. fill radiator to the top of the neck.. close it up.. run 10 min under load.. let cool. take off radiator cap and check.. add coolant.. run 10 min under load. let cool.. I did that 6 times before the coolant stayed at the top of the neck. The last time I checked it I only added a tablespoon or 2.
2004 Holiday Rambler Endeavor DST,07Chevy Colorado
Jefferson City, Missouri
Navy Viet Nam vet 67/71 USS Decatur DDG 31