Q: My 2002 E46 is fast approaching 100K. Is it really imperative to replace the water pump and thermostat as preventive maintenance on this car? Can't I just wait until the unit fails (if it fails at all)? What are the early signs of water pump and/or thermostat failure? Thank you.
A: Brod must never owned a BMW to say "why fix something that isn't broke" . YES, you should replace the waterpump and thermostat. The reason why is the pump can give out causing the car to overheat or like mine, the pump bearing gave out allowing the attached fan to chop up everything in my engine bay ( belts ,pulleys,radiator etc) . Likewise a $20 thermostat could end up costing you much more if it gets stuck open or closed.