[bimmerquick43321]

this is a little bit priceless, so it's been 3 years I have my e90, I usually change cars ~2years, so not long ago I started thinking about buying something else, that being said because of kids, life priorites, etc.. I thought I would get something more sensible/economical in the new...


Ok so on my way home from work today I was looking on the road on some new subcompact cars, and saying to myself in my head like no freaking way I'm getting a stupid little toy car, I like my bmw, it's well build, bla bla bla, at that moment my high coolant temperature came on to put me back in my place and let me know my water pump is done....

BTW. hassmachine I didn't get any check engine light before it happen (I'm running your modified rom), I do have it now though, with the water pump related codes....

Was lucky as it happend literaly a few minutes away from home, so I waited a few hours for it to cool down and than went back and brought it back home safely (while monitoring the temparture with my OFT), tomorrow it's getting towed at the garage, the day after I'm leaving for vacation in the republic dominican lol

[TheSt|G]

The issue is that the codes for the water pump failing aren't designed for the reason it fails.

[hassmaschine]

explain? how does the pump fail? I don't think anyone knows. it's *not* water getting into the electronics.

there are errors for pump overcurrent and pump underspeed. if anything were to give an advanced warning, it would be those. that's too bad, it was worth a try though. probably worth leaving them enabled anyway, because the pump might still fail in those modes.

[TheSt|G]

Originally Posted by hassmaschine

explain? how does the pump fail? I don't think anyone knows. it's *not* water getting into the electronics.

No? I was under the impression it was much like the shaft sensor. Who disproved that?

[Delta0311]

Yeah I know what luck right!! Had the window regulator fail in my E90 2 days before I was going to Jamaica. And the other regulator failed as I was about to go to a wedding. It's like BMW times this shit perfectly. I think it's Germany's revenge for their defeat in WWI and WWII.

[mmmnot]

Originally Posted by TheSt|G

No? I was under the impression it was much like the shaft sensor. Who disproved that?

Per my experience working in an industrial company with valves and pumps, generally pumps fail due to bearings being worn and causing play. Once that happens, seals are the next 'weak point', which causes a snowball effect.

I'm just bored at work, so don't take this as a mechanical quote.

[TheSt|G]

Originally Posted by mmmnot

Per my experience working in an industrial company with valves and pumps, generally pumps fail due to bearings being worn and causing play. Once that happens, seals are the next 'weak point', which causes a snowball effect.

I'm just bored at work, so don't take this as a mechanical quote.

Sure, I agree that could happen(and what the codes are designed for), but I thought I remembered people in the past chopping up the water pumps to see what failed and it was coolant fouled electronics.

[hassmaschine]

Originally Posted by TheSt|G

Sure, I agree that could happen(and what the codes are designed for), but I thought I remembered people in the past chopping up the water pumps to see what failed and it was coolant fouled electronics.

where did you see that? because I read everything I could find on people dissecting their pumps and saw the same thing I found - the electronics were bone dry. And the amount of people who are taking them apart to see the cause of failure compared to the number of pumps being replaced is vanishingly small. I think I found two.

[mmmnot]

Originally Posted by TheSt|G

Sure, I agree that could happen(and what the codes are designed for), but I thought I remembered people in the past chopping up the water pumps to see what failed and it was coolant fouled electronics.

Again, this is where my car mechanical ignorance will shine, but assuming a water pump functions with the same theory and principals as a standard industrial actuated water pump - this would make logical sense.

Assuming there are bearings and moving parts that cause friction and play, it could easily wear down a seal/gasket or retaining bracket to cause the leakage into the electrical areas.

But on the same theory/note - aren't there electronics is the 3 stage intake manifold which gets flooded with oil? Perhaps one liquid is more conductive than the other. Shrugs.

[hassmaschine]

the electronics are on the opposite end of the pump from the motor. again, I haven't seen anyone post that the electronics got wet. that is assumed. if there have been 5,000 pump failures and 3 people have taken them apart and posted the results, two said they were bone dry and one said it had water damage, none of those results say anything about what the broader cause of failures are.

[TheSt|G]

Originally Posted by hassmaschine

where did you see that? because I read everything I could find on people dissecting their pumps and saw the same thing I found - the electronics were bone dry. And the amount of people who are taking them apart to see the cause of failure compared to the number of pumps being replaced is vanishingly small. I think I found two.

I frankly never really paid much attention to it. My interest was in what the safe preventative maintenance interval would be.

[bimmerquick43321]

Originally Posted by Delta0311

Yeah I know what luck right!! Had the window regulator fail in my E90 2 days before I was going to Jamaica. And the other regulator failed as I was about to go to a wedding. It's like BMW times this shit perfectly. I think it's Germany's revenge for their defeat in WWI and WWII.

Never went to Jamaica I'm planning my next trip thethere, how did you like it?

[bimmerquick43321]

Originally Posted by hassmaschine

explain? how does the pump fail? I don't think anyone knows. it's *not* water getting into the electronics.

there are errors for pump overcurrent and pump underspeed. if anything were to give an advanced warning, it would be those. that's too bad, it was worth a try though. probably worth leaving them enabled anyway, because the pump might still fail in those modes.

I actually did get one of the codes related to the pump underspeed, not sure if it happened in the same time the pump failed or before, if before I'm guessing I would of gotten the engine light as a warning oh well shit haapens I guess

[hassmaschine]

Yeah i set it uo to trigger the light. Disappointing that it didn't provide a warning, but i guess we now know ppreventative replacement is he bes solution since failure is sudden.

I'd still like to know why they fail, but further dissection of a failed pump is way down on my bucket list.

[bimmerquick43321]

btw. I got my car after getting back from vacation, runs like new now and my conscience as well, knowing I won't be left stranded and possibly damage the engine because of stupid water pump...

[alexwhittemore]

Originally Posted by TheSt|G

Sure, I agree that could happen(and what the codes are designed for), but I thought I remembered people in the past chopping up the water pumps to see what failed and it was coolant fouled electronics.

I never got around to writing it up, but I broke open someone's failed 335 pump a while back and there definitely wasn't any liquid penetration. Even if there had been, all of the control electronics are potted in a gel to keep environmental contaminants out. In fact, the motor is designed with the stator inside a hermetically sealed housing, with the rotor inserted into it on the other side of the housing. That way, there's complete electromechanical separation from components exposed to coolant and electronics. Short of an impact breaking the casing, the motor would fail and stop turning well before there'd be any possibility for coolant penetration.

That said, that's the 335 pump. The N52 pump is different, I just don't know by how much.

[hassmaschine]

I think they're basically the same. the 335i just has a little higher capacity. the pump I took apart (N52) was the same as you described above. There's no real way for water to get inside, and even if it did, everything is sealed.

[TheSt|G]

Fair enough, so any thoughts on the cause of failure?

[hassmaschine]

I'm willing to bet whatever IC actually drives the motors overheats and burns up. basically something electronic that either isn't well protected or is undersized.

Unless the motor itself burns out (is it brushless?). I've thought of trying to supply power straight to my dead pump and see if it will still turn over. The pump motor itself could be the part that dies.

[alexwhittemore]

Originally Posted by hassmaschine

I'm willing to bet whatever IC actually drives the motors overheats and burns up. basically something electronic that either isn't well protected or is undersized.

Unless the motor itself burns out (is it brushless?). I've thought of trying to supply power straight to my dead pump and see if it will still turn over. The pump motor itself could be the part that dies.

An IC "burning up" as such wouldn't really make sense - you wouldn't get the kind of intermittency people report. The second anything went wrong, it'd go hard wrong. In either of the cases of IC burn up or coil burn up, you'd see huge power draw, and that power draw code would be thrown.

Obviously there's some other age-related fatigue failure, which certainly could be in an IC.

As far as the motor itself, yes, it's brushless. It absolutely requires a functional controller to turn.

[hassmaschine]

I guess it depends on the mode of failure. Sometimes an IC can fail without any signs of overheating.. anyway, it's just a theory. I can't think of any other ideas, if the motor is brushless then it's almost certainly something on the PCB that fails.

[El Cheapo Loco]

Originally Posted by mecbain

... knowing I won't be left stranded and possibly damage the engine because of stupid water pump...

I thought the same after I replaced my WP, until a month later I was stranded because of the stupid starter...