Have you any diagnostic equipment like planet to check for faults logged..??
The cooling fan system is pretty complex on these as the dpf brings on the cooling fan during a regen...I think there were a few cases where a faulty turbo control on these were bringing on the cooling fan most of the time....dont no how they are related but replacing the turbo solenoid sorted it.....best things is to get faults read instead of fitting parts that are not requird..
Ron.