mrwrenchman wrote:
I have a 2006 Monaco with a 8.8L 400HP Cummins side radiator . Recently I noticed the engine fan is running full speed all the time . I know the fan is driven hydraulically and I think it thermostatically controlled . Is there a thermo. control valve somewhere that is possibly stuck in the wide open position , or some other condition .Any Ideas ? Thanks Don
We had the same problem with our ISL 400, and it ended up being the hydraulic fan controller. I took it to Cummins Cal Pacific and described the same symptoms - Fan running at full speed all the time (tons of dust every time we pulled into an unpaved campground) and they found the failed part. I can't remember exactly what it was called, but it was a part that opened and closed a valve on the hydraulic lines that drive the fans. At least it was stuck open so we weren't overheating.
If you need more details I can call Cummins and ask them.