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      08-20-2011, 07:21 AM   #18

Drives: 2006 325i Sport
Join Date: Jun 2006
Location: Virginia

iTrader: (0)

Originally Posted by queensfield View Post
Does the frequency of coolant change has anything to do with water pump and/or thermostat failure. From Eninty's thread, I understand that the coolant was changed around 75K, if I remember right. Anyone has any exprience with coolant flushes and water pump failure. I am a power electronics engineer and I work on electric motors. I can tell you that the motors are well built, but the electronics is not. Silicon electronics do not last long when driven past 70C ambient, which in most cases results in 125C at the semiconductor junction.
queensfield, when I pulled the rear cover off my old pump, it looked like to me the conformal coating had vaporized and then resolidified on the inside of the housing where the electronics reside. The electonics module is bolted and pinch-welded into place and you can not see the circuit board because it is underside of a plastic cover on the module. The only think visible in the electronics module is a capacitor and two wire coils. I really think that as the pump ages, the electronics become more susceptable to heat falure.