I am new to diesel pushers (and class A coaches in general) but have jumped in with both feet!! I have just purchased a 2008 Gulfstream Tourmaster 40B coach with the Cummins ISL 425 HP engine on a Freightliner chassis . The coach has been very lightly used with only 16k miles and 40 generator hours. When first started, and for 5-15 minutes afterwards, the radiator fan cycles every 5 seconds or so between gale-force wind with lots of noise and almost no air or noise. After everything is completely warmed up it seems to behave. The engine temp seems normal - around 190°. Other noises that remind me of a bad bearing (squalling/grinding) are barely audible as the fan cycles, but with no experience with big diesels these may just be normal. I could probably make a recording of the sounds and post it if it would help. Can anybody put my concerns to bed, or do I need to find a Cummins shop before the fan screws itself through my $$$ radiator? We're looking forward to meeting all of the great folks as we begin to venture out from our corner of the country. 10 years from now we may be 8 year full-timers!