BMW E90 electric water pump: failure and bleeding
How long does the E90's electric water pump last and how do you notice a fault?
In N52 and N53 engines pumps have failed at around 120,000-250,000 km, most often between 150,000 and 200,000 km. Lifespan varies a lot. A fault shows up as a rise in temperature: a yellow warning comes at about 120 degrees and a red one at about 130 degrees, at which point engine power drops.
What do fault codes 2E81 and 2E82 mean?
2E81 means a deviation in the electric water pump's rotational speed and 2E82 means the pump has been switched off. When replacing the pump, it is worth replacing the thermostat at the same time. The pump and thermostat housings are plastic, and a leak usually only shows when hot, when the system is under pressure.
How is the cooling system bled after replacing the pump?
Bleeding is done with the bleeding program: ignition on, heating on hottest and the fan on lowest, throttle pedal fully down for a good 10 seconds until the pump starts. Bleeding takes about 12 minutes, so connect a battery charger. A three-minute bleed is not enough. Fill the coolant through the bleed screw and keep the cap closed during bleeding.