Overheating 2004 Tiffin allegro bus 36 OP cat. 3126 e 330 hp

Check the hoses to the radiator for a partial collapse, especially the one going to the radiator. Sometimes the inner liner will have a hole in it and allow a bubble form inside and restrict the flow, and eventually get bad enough to block flow completely. A soft mushy spot will be a dead give away, the system must be unpressurized when you start squeezing hoses, or you won't be able to feel anything. Sometimes you won't be able to tell by squeezing, only by cutting it open lengthwise.