One problem related to radiator has been reported for the 2007 BMW 530. The most recently reported issues are listed below.
This vehicle, unlike all other BMW automobiles has no rock guard in place on the lower front bumper protecting the radiator, etc from road hazards. A rock was thrown by a vehicle in front of me that pierced the condenser attached to the front of the radiator resulting in the car being taken to a service center on a roll back. I see this as a design flaw, (corrected on the 08 model), that can result in dangerous driving situations.