BMW E90 Electric water pump?

[strictlybeamers]

Hello everyone

Has anyone bothered to open their e90 bad electric water pump? I opened mine and inside it looked like an iPhone guts. Just out of curiosity, why it has to be so complex.

I took some pictures while tearing this down, Someone please help me understand the process

[cochise325]

Good questions. The basic premise it that by decoupling it from the flywheel, you can make it variable speed, and run it even after the engine is off to help cool down the engine. Supposedly it saves energy, because it runs at slow speeds when it is cold outside, and this even helps the engine warm up faster. The turbo motors generate a lot of extra heat, so being able to run it after the engine is off is beneficial. Now they just need to figure out how to make them last a lot longer.

[02325]

its a BMW, when have the engineers ever done something simple. they have to have a control module for everything.

[ndog14]

It's nice to have the REST feature during the winter months.

[mystreba]

Great idea pulling it apart - thanks for posting.

It's tempting to think of it in simple terms of one variable - engine temperature - but in reality there are many components with requirements, variables, checkpoints and sensors that might have something to say about coolant flow. Engines are so complex these days (smaller, lighter, more powerful, more efficient) that the old mechanical concept of a continually running water-pump controlled by a thermostat operating on a single variable are long gone.

I can't recall exactly from when I replaced mine, but I don't believe the thermostat is electronic. You'd think it would want some control over the flow out to individual drive train components.

In the end it was likely mechanical failure of the pump impeller/thermostat valves that did it in.

[fun2drive]

The circuits look like that for a brushless motor the cap is there to keep voltage spikes under control as it switches phase. A lot of the circuitry is for for motor drivers.
I wish I could see the motor and trace the wiring back to see how it is constructed.
Did any of the electrical components look burned? Is that yellow phenolic casing that the impeller is housed in cracked? Would the impeller turn without much resistance?
Sorry for the questions and I hope someone else more familar with small motor technology can pitch in.

[Pilgrim]

Because it's German-made. The Germans decide what is the "correct" way, and no matter how complex that is, they implement their "correct" design. You will enjoy it - that's an order!!

[nickvacc]

So that's why mine failed at 45k :p

[hypnoticautopsy]

LOL, yea it at first when mine failed after cussing a bit and crying about the cost BMW quoted me to replace, I was like why the HE-DOUBLE-L would BMW make an electric water pump... then when I purchased it from Tischer for hella cheaper and replaced it myself... I was like WHOO-HOO, that was the best idea ever!! I didn't have to dismantle my motor just to replace the water pump... took me 4.5 hours and 8 beers, vs 8 hours on my DC2 (94 Integra), 9 hours on my soarer (sc300)