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Discussion Starter #1 (Edited)
My headlamp washer pump stopped working a while ago. I heard the motor running, but the impeller was not spinning. I figured the impeller must have been disconnected from the motor somehow. After replacing the pump, I gave the old broken one to my engineer room mate who figured out how to take it apart.



This is the case. It's near impossible to get off because that ridge fits into the other case to create a water-tight seal.




Here's the ridge




Here's the groove that the ridge fits in. You can kind of see it, but once the case is connected, it's very difficult to get off apart from almost destroying it. It's still usable now, but not as good of a seal as before.




Here's the impeller motor. It's just your standard motor. If you're an engineer, or go to an engineering school, you're bound to run into one of these. You'll find these in microwaves, too. It's pretty powerful. Hook up a 12V power source to it and it spins pretty quickly.




Capacitor at the top of the motor.




And here, my friends, is the source of probably all of the reasons why the headlight pump fails. This little impeller is the most brittle piece of plastic I've ever held. The smaller piece you see there on the right was the one that was actually broken off from the larger piece on the left. The long piece broke off of the larger piece in my hand when I picked it up - it's that fragile. Something that spins so quickly should be durable at the very least. It makes sense now why the motor sounded like something was spinning around in it when I initially tested it.




The impeller fits through this seal, which prevents washer fluid from getting into the motor and the housing in general.

And that's the inside of your headlight washer pump. I'd imagine your windshield washer pump is very similar, if not the same but with a smaller motor.

If this ever breaks on you, do yourself a favor: buy an aftermarket one. It's literally the exact same thing. I cannot find any difference between the two other than one says BMW on it. You can buy 3 of these pumps for the price of one BMW pump.
 

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Good read :thumbup:

I originally thought my car had a coolant leak, but it turned out to be my driver side headlight washer, great success!
 

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This is a beautiful write up! We need more people like you, putting legitimately useful information onto the forum, THANK YOU FOR YOUR CONTRIBUTION and keep it up. Two thumbs up
 
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