Water Pump Brand Conversation

[digger]

My memory, without looking, was that they claimed the S54's water pump flowed something like 30-50% more than the S50B32's, thanks to the updated impeller design. It was not an insignificant increase.

yet you still see counless threads on cooling issues and people wanting fancy radiators and electric fans, because the pump flow is not the governing thing......

[Obioban]

yet you still see counless threads on cooling issues and people wanting fancy radiators and electric fans, because the pump flow is not the governing thing......

“BMW did such a good job with the pump that you never see people upgrading it” 😄

[JakeM346]

yet you still see counless threads on cooling issues and people wanting fancy radiators and electric fans, because the pump flow is not the governing thing......

Yeah but…….noooooo….…the oem pump has a 62% increase in flow efficiency in its best point in comparison to the s50 pump. This is needed for the cross flow coolant design that the S54 utilizes (more flow needed). Therefore it’s stupid to compare S50 and S54 coolant pump and especially metal impellers. Metal impellers will simply not bring the requested flow.

Also you brought in valid points but got to the wrong conclusion. Flow is extremely important. Many of the coolers actually try to improve overall coolant flow by reducing flow resistance and more importantly you basically also said that the oem pump flow is so good that it’s not the „bottleneck“ in the cooling system, because if it would be people would change it‘s size/pulley size.
The oem pumps are great quality and the plastic impellers normally don’t explode for the S54 unless your bearing is already so worn out, that it starts to wobble. This actually happens to most people but then instead of finding the root cause the say ….“oh noooo……plastic badddddd….want cheap metal“ like freaking caveman.

[JakeM346]

So I've had 4 water pumps blow up...hear me out...they were all pulled them from damaged S54s. All over 100k except for one.

Two had the impeller disintegrated.
Two had the backside of the bearing explode and leak grease into the coolant system. To this day, my coolant comes out cloudy and gray. It has gotten a lot better as I've drained the system more often.

I think BMW has a long 30 year history of shiet coolant systems. The plastics have improved over the years...lol... but it is still an issue.

For any BMW, 100k water pump change as preventive maintenance if it makes it that long.

Track car, have a spare on hand.

Isn’t like a 100k already over the change interval. This is like freaking long….if I think about Porsche/Mercedes and VW all saying about 60000km or max 100000 km which is actually way under 100k miles.

so yeah I agree change at 100k miles the latest and probably also safe to say every 10years

[PurelliCondoms]

Ok, so as a community it seems very clear that the plastic/resin OEM water pump is the best and only real option. That being said, these pumps are going to be NLA sooner rather than later as everyone has mentioned. So, what do we do about it besides horde parts? Is it possible to contact a manufacturer that can build us a pump or figure out how to rebuild the oem one?

[JakeM346]

Ok, so as a community it seems very clear that the plastic/resin OEM water pump is the best and only real option. That being said, these pumps are going to be NLA sooner rather than later as everyone has mentioned. So, what do we do about it besides horde parts? Is it possible to contact a manufacturer that can build us a pump or figure out how to rebuild the oem one?

Rebuild, might work but only last for a couple of years till the plastic ages.
I don’t think bmw will actually stop producing the water pump or we might see the IP Contract run out and following maybe the OE manufacturer selling the pump directly to us

[chris719]

BMW let the injectors go NLA, so why not the pump 😂.

[Altaran]

Ok, so as a community it seems very clear that the plastic/resin OEM water pump is the best and only real option. That being said, these pumps are going to be NLA sooner rather than later as everyone has mentioned. So, what do we do about it besides horde parts? Is it possible to contact a manufacturer that can build us a pump or figure out how to rebuild the oem one?

Contacting a rematurfacturer would likely be the only viable solution.
Building an entirely new one is not going to be economical, the tooling amortization for casting the housing is going to be a big impact on price with the low aftermarket volume. In addition, the OEM casting is likely to be better quality than anything aftermarket.
What's left after that is just a shaft, seals, and impeller. As discussed above, making the impeller out of an OEM-like hydrophob polymere is going to be the main point. Tooling cost for an impeller should not be too expensive, likely less than 2k.

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[chris719]

Do we even know who makes the pump? I read somewhere the impeller was sourced from Nidec.

[JakeM346]

Do we even know who makes the pump? I read somewhere the impeller was sourced from Nidec.

Yeah nidec I’ve heard too. However the impeller incl. the Pump is most likely all BMW designed which is why we don’t see any aftermarket OE pump since it’ll probably be protected as Intellectual Property.
Nidec also makes sense since the Housing of the pump is marked GPM and there is Nidec GPM which is specialized on water pumps.

[Chanman1029]

Not sure if it was already mentioned, but here’s another reason to avoid a metal impeller. One time on non-m e46, the bearing broke on my water pump which allowed the shaft to come out of place and move a great deal. The composite impeller inside struck the inside of the water pump housing inside the block, and broke onto a bunch of tiny plastic pieces.

Now imagine what might have happened with a metal impeller, possibly chewing metal from the block, causing irreparable damage.

After experiencing that first hand, I’ll never even think about a metal impeller.

[discoelk]

So much confidence in which parts are "best", yet no empirical data.

YMMV.

[JakeM346]

So much confidence in which parts are "best", yet no empirical data.

YMMV.

I mean there is empirical data. According to BMW the Plastic impellers achieves an overall effectiveness of 62% in its best point. Also according to bmw this is necessary to achieve the flow required for the cross flow cylinder head design……

[chris719]

All we need to know is BMW pumps usually last 100k and some others don’t even make 20k if you’re unlucky.

[PSUEng]

Just ordered me a Genuine pump. Who's paying $400+?