I was warned by the computer system of engine over heating, and while driving on freeway, the engine automatically slowed down the speed, which caused me pull of the freeway in a hurry, so I wouldn't cause any accident for slow traffic. At the mechanic's shop, I was first informed that thermostat was defective, but later they discovered the water pump has failed. The reason for the water pump failure was because the electronic control within the water pump housing appeared to be burned out. I was able to see the burned charred mark on the interior wall of the housing, which is laminated with plastic. The water pump is in close proximity of the engine. This failure happens at about 10,000 miles after the expiration of 50,000 miles warranty. I believe the design of the water pump and the location of the water pump has inherent problem for eventual breakage. BMW should redesign this part.

- Arcadia, CA, USA