I am concerned that if the water pump and/or thermostat fails then my family or I could be stuff at a inconvenient time / place. This there a guideline when these items should be replaced (year and/or milage) to be prudent. This car is going on its 12th year and we plan to keep it for the foreseeable future. Thanks
How Often Should Water Pumps / ThermostatsBe Changed on 1999 BMW 328i
by smbmw7 in Santa Monica, CA on January 29, 2010
ANSWER by patrick mannion , January 30, 2010
The thermostat usually gives warning of lower running temperature or poor heater output if it fails open and over heating if it fails shut. I would change the thermostat next cooling system flush if it has not been changed in the last 6 years, 60,000 miles. Waterpumps on some cars in particular are an issue or common failure. Some VW, Audi,Jaguar and BMW have the water pump impeller fall off. The water pump is not really a maintenance item . Call a local independent BMW shop in your area and just ask them do they see a "pattern failure " of water pump issues with your model year and see if they recommend replacement.
ANSWER by jboat1 , April 18, 2010
i changed mine @ 115000 or so it started making noise but I got 145000 out of my 525i
ANSWER by rhuntguitar , October 16, 2015