NHTSA Preliminary Evaluation PE11036

In a January 10, 2012 letter to NHTSA, BMW of North America, LLC. (BMW) submitted a Defect Information Report (DIR) identifying a defect in the electric auxiliary water pump in approximately 88,911 model year (MY) 2007-2011 Mini Cooper vehicles manufactured from November 14, 2006 through January 18, 2011 (Recall 12V-008).According to BMW, the auxiliary water pump on vehicles equipped with 4-cylinder turbocharged engines may overheat.Electro-migration can cause the pump electronic circuit board to overheat resulting in smoldering of the water pump. If smoldering occurs, it may lead to an engine compartment or vehicle fire.The pump supplier, Pierburg Pump Technology GmbH, redesigned the pump to address factors that may contribute to circuit board overheating.The redesigned pumps were completely implemented in production vehicles by January 2011.Recall 12V-008 was the third recall initiated by BMW to address electric auxiliary water pump fires in vehicles equipped with Pierburg pumps.In two October 20, 2011 letters to NHTSA, BMW submitted DIRs for similar auxiliary water pump defect conditions in approximately 32,084 MY 2008-2011 BMW 5-Series, 7-Series, X5 and X6 models equipped with 8- and 12-cylinder engines and manufactured from May 2008 through December 2010 (Recall 11V-521); and for approximately 589 MY 2010 Rolls-Royce Ghost vehicles manufactured from September 2009 through September 2010 (Recall 11V-522).In three separate April 5, 2012 letters to NHTSA, BMW submitted amendments to Recalls 11V-521, 11V-522 and 12V-008.The amendments all described a common defect condition related to a manufacturing process deviation in a certain production range of the redesigned Pierburg water pumps that could result in cracks in the pump housing, which may allow coolant to enter and contact the pump?s circuit board.BMW indicated that further analysis identified a specific machine process error at the sub-supplier that manufactures the water pump housing.Pump housing cracks may