Thanks Volvoman. The Kenworth shop near me said pretty much the same thing. They also said to check it with the test strips Geof. They sell the Cat conditioner too and said it's good to use. I'm planning on draining as much out as I can, then adding water and running it a bit, then drain, then add 3 bottles of Cat cooling system flush. Then top off with water and run it for 90 minutes at operating temp. Then flush it all out a few times with water. Then drain it as much as possible. Fill with 6 gallons of Cat coolant, not the extended, just the regular Cat. Then top off with distilled water and add conditioner. That should about do it. After that I'm going to flush out the generator coolant too.
'03 Freightliner FL112, 295" wheel base, with '03 United Specialties 26' living quarters, single screw, Cat C12 430 h/p 1650 torque, Eaton 10speed , 3.42 rear axle ratio