One problem related to water pump has been reported for the 2008 BMW X3. The most recently reported issues are listed below.
My BMW had been having a roaring, vibrating noise in it. Then it started running hot. I parked in my garage only to find water and antifreeze all over the garage floor. When I took it to get it fixed, the mechanic told me that the bolts which hold the engine mounts up on the passenger side had broken and the engine was sitting sideways and had dropped down and crushed the water pump and coolant reservoir. The bolts are not substantial enough to support the engine. They are very lightweight metal (maybe aluminum) and just broke. The car has not been involved in any crash. There is no reason why the bolts broke, but it could have really put my family in jeopardy. When I contacted the dealer to see if there had been any recalls on these bolts, they acted like I was crazy and didn't know what I was talking about.