[oilcrankinject]

My water pump went out at 54k. I am at 102k and I am worried that I am due for a new water pump.

I would really like to know what causes the pumps to fail.

[Emilime75]

From what I've read, it's either a leak at a manufacturing seam where two pieces are bonded together or a failed motor. I think I've also read about plastic impellers breaking(although some have said N54-E9x pumps have metal impellers).

That electric water pump has quite the challenge of surviving in such a harsh environment. It's surprising it lasts as long as it does, really.

[mj6234]

I replaced my original at 42k. At 122k now and am going to proactively replace it over Christmas. They wont last forever....

[oilcrankinject]

Does anyone have a failed water pump that I could play with?

[mweisdorfer]

Originally Posted by svtfast

My water pump went out at 54k. I am at 102k and I am worried that I am due for a new water pump.

I would really like to know what causes the pumps to fail.

You can plan on a water pump lasting around 75,000 miles or so on average. I got 108,000 miles on my first one. However, I'd say that I was probably my water pump was in the top 10%, in terms of longevity.

Anyone, that would take the water pump and find a way to upgrade the internals would probably be a millionaire. You'd probably want to find a way to make it all aluminum casing.

Maybe just putting a heat shield around it? It's near the two turbos, so that probably doesn't help.

[KOTI]

I just had my water pump and thermostat go at 122K and I have a theory as to a common cause for premature failures.

The average owner doesn't know they cannot mix coolants. This mixture can react and cause expansion in hoses and/or ruin a gasket. Once the gasket starts to allow coolant to leak, it starts to form air pockets or big gaps. The electric water pump motor will have some sort of controller limiting the RPM, however, the motor is designed to be moving coolant through a closed loop system. When air is introduced, the motor will spin at full speed and heat up so much that it will kill itself. This is why the bleeding procedure is so important. Any time you add even a dash of coolant to your system make sure to bleed the system with the proper procedure. My theory as to why this is more prevalent in these electric water pumps is they are not connected to the engine with a belt. That connection theoretically limits the max water pump speed, and could help to preserve the pump's life.

Thoughts?

[feuer]

Originally Posted by KOTI

I just had my water pump and thermostat go at 122K and I have a theory as to a common cause for premature failures.

The average owner doesn't know they cannot mix coolants. This mixture can react and cause expansion in hoses and/or ruin a gasket. Once the gasket starts to allow coolant to leak, it starts to form air pockets or big gaps. The electric water pump motor will have some sort of controller limiting the RPM, however, the motor is designed to be moving coolant through a closed loop system. When air is introduced, the motor will spin at full speed and heat up so much that it will kill itself. This is why the bleeding procedure is so important. Any time you add even a dash of coolant to your system make sure to bleed the system with the proper procedure. My theory as to why this is more prevalent in these electric water pumps is they are not connected to the engine with a belt. That connection theoretically limits the max water pump speed, and could help to preserve the pump's life.

Thoughts?

Ok, and how do you explain, on my own n54, 1st replacement at 4y/38k and 2nd replacement at 8y/78k ? I have never used anything but BMW coolant since I get it very cheap, maybe $12/gal. Since I work in a repair shop I have replaced many. You theory is major fail, in both parts, for mixing coolants and having the system bleed after every fill up. Issue/reasons of these pumps failing has been covered in many thread in past.

[TemjinX2]

well your putting a electric component onto a hot engine in a location that can get water and mud, which are all horrible environments for electrical components.

Probably not worth trying to re-engineer, BMW didn't think so and went back to a mechanical water pump with the b58 motor.

So just take it as the nature of electric water pumps and include it in your preventative maintence costs.

My cousin went through 2 electric water pumps on his mkvi gti at under 45k miles.

[oilcrankinject]

Is it possible to fit an aftermarket electric water pump and to move to part of the engine bay that is cooler (and easier to get to)?

[Emilime75]

Like anything else, anything is possible with the investment of funds and engineering into it. Wether or not that investment is practical, or worth the results, is an entirely different question. You'd basically have to produce custom machined parts, modify wiring, find a suitable location...

[oilcrankinject]

I would need to know the flow rate of the OEM pump before proceeding. Moving or extending wiring is ez but matching flow rates and hose sizes is not.

[Emilime75]

Might be better just to relocate the stock pump.

[drunkenup]

Originally Posted by Emilime75

Might be better just to relocate the stock pump.

It's been done. A guy on one of the N54 facebook groups moved that plumbing medusa into the space behind the left headlight on his 535i.

As far as BMW abandoning the electric pump, not really true. The S55, N63, and B58 have belt driven pumps but have an electric pump on the turbocharger's circuit. Probably for redundancy but retaining control over water temps

If OP wants to pay S&H, I have a failed N54 and N52 WP sitting in my garage

[techwhiz]

Replaced mine a couple of months ago with about 100K miles on it.
Previous one went at 80K.

[4 Doors]

Just to chime in on longevity, my water pump just went out yesterday at 122,000 miles. The original pump was replaced at 65,000 miles. Average longevity, from what I have read, is about 60,000 miles. Best to replace proactively as maintenance if possible. Also, agree with the above, finding a new location may not be worth the trouble imo.

[Torgus]

Originally Posted by svtfast

Does anyone have a failed water pump that I could play with?

I have my OEM stock that I removed at 90k. It is the metal design and not the plastic. I believe earlier models got the metal body and later the plastic body. You are welcome to it if you want it. It ran fine before I removed it.

[TheMidnightNarwhal]

Originally Posted by Torgus

I have my OEM stock that I removed at 90k. It is the metal design and not the plastic. I believe earlier models got the metal body and later the plastic body. You are welcome to it if you want it. It ran fine before I removed it.

Oh wow some N54 had metal designs?

That's nice, I suppose the metal design prevents any leaking failure and only leave failure of the pump by electronics?

[TemjinX2]

Originally Posted by drunkenup

It's been done. A guy on one of the N54 facebook groups moved that plumbing medusa into the space behind the left headlight on his 535i.

As far as BMW abandoning the electric pump, not really true. The S55, N63, and B58 have belt driven pumps but have an electric pump on the turbocharger's circuit. Probably for redundancy but retaining control over water temps

If OP wants to pay S&H, I have a failed N54 and N52 WP sitting in my garage

the water pump for the engine is mechanical on the b58...only the water pump (intercooler pump) for the intercooler for the b58 is electric since its a air to water system charged system for the turbos versus the air to air charged system of the N54.

a dead electric pump on a intercooler will only make the charged air temps go up so not a big of a deal as preventing a motor from over heating.