I have no suggested solutions to the originator for his problem. I do have a similar problem that is not being solved by the various garages that have serviced our 2007 Newmar Ventana for overheating/shut down engine warning light and buzzer. Thus far our coach has had 5 clutch fans replaced, 1 thermostat, engine belts, fan control solenoid, shroud at rear of radiator stack to prevent hot air from being pulled back into the engine compartment, and the coolant drained and replaced. Our coach has a rear radiator. Our most recent failure occurred on 6/29/12. At the present time we are in Fort St. John, BC, Canada at a Rotary RV Park waiting for Cummins dealers to open, it's Canada here and many are closed for the holiday.
Clearly repairs that have been made in the past have not gotten to the root cause of the problem. When the clutch fan goes it has to be replaced, the friction disk is worn to the point it can no longer engage the fan and the engine overheats. Thus far none of the shops have mentioned having cleaning the Charge Air Cooler (CAC), or any other part of the radiator. Could this be the problem?
When the system is operating properly, the engine temperature cycles between 200° and 212° and I can hear the fan cycle on and off. When the engine overheats, the temperature continues to rise and I can no longer hear the fan cycle on.
We're spending $$$$$ to have each of these clutch fan assemblies replaced. If anyone has insight as to the root cause of the problem, it would be greatly appreciated.
John Smith
2007 Newmar Ventana Diesel pusher
