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

I had an intermittent overheating problem. Didn't lose any coolant, the gauges and warning buzzer went wild. Freightliner in Springfield, Mo, couldn't find the problem, hoped that downloading updates would cure the problem. Updates didn't help at all. Problem got increasingly more frequent. Freightliner Service Center in Gaffney found the problem, the fan clutch was slowly, very slowly leaking oil. As it leaked more, it overheated more often. Got that replaced and it ran like new, until the turbo went out 2 days later!!!