Two problems related to car stall have been reported for the 2005 BMW X5. The most recently reported issues are listed below.
Engine iced up and hydro-locked from condensate. Stalled in traffic with slippery roads, in front of a logging truck. Very narrowly escaped collision. Found many incidents of this on internet and it appears that BMW has allowed this to continue over time and is not acknowledging issue. Repair shop I'm using has dealt with many incidents of this, too. Used for 17 mile each way daily commute so short trip-related problems should not be an issue.
The contact owns a 2005 BMW X5. The contact stated that while driving approximately 55 mph, the vehicle would stall without warning. The vehicle was towed to the dealer who informed the contact that the failure was caused by the oil separator. The vehicle was repaired. The failure mileage was approximately 83,000. Updated 02/10/11 updated 04/21/11.