Guide: Replacing Water Pump and Thermostat - E89 N54 (and radiator)
- Thread starter Christopher72
- Start date
Scottish Borders
Ohio
B21 said:
Very true.. especially on the softer aluminium bolts! etorx/torx socket sets are fairly inexpensive, if yours are torx/etorx, there are flex head socket wrenches as well.
I was thinking more like https://www.amazon.com/dp/B0C8STLVN...XHMTMQPC2VYDX6NFT&starsLeft=1&skipTwisterOG=2 mated with a torx/etorx socket
So I ended up removing the steering column since it actually was not that difficult.
Once I removed it I realized that it was a required step no way could I have gotten such a clear shot to the bolts without it off.
I'm going to post two videos that helped me remove the steering rack for others
Here are some pics for the location of the bolts.
Once I removed it I realized that it was a required step no way could I have gotten such a clear shot to the bolts without it off.
I'm going to post two videos that helped me remove the steering rack for others
Here are some pics for the location of the bolts.
Angel_e39 said:So I ended up removing the steering column since it actually was not that difficult.
Once I removed it I realized that it was a required step no way could I have gotten such a clear shot to the bolts without it off.
I'm going to post two videos that helped me remove the steering rack for others
Here are some pics for the location of the bolts.
These look excellent instructions, however, I have an N52 3.0litre.
I cannot find specific " N52 how to" on this forum; can I follow this successfully, or can someone please point me in the right direction?
I am concerned about buying the appropriate torx spanner.
Thank you.
I cannot find specific " N52 how to" on this forum; can I follow this successfully, or can someone please point me in the right direction?
I am concerned about buying the appropriate torx spanner.
Thank you.
Car is past 130k now and Welsh roadtrip at Christmas planned so keen to replace pump before.
Once again can I ask if this guide can be used for my N52?
Once again can I ask if this guide can be used for my N52?
I'm sorry Blue, I didn't see this thread light up -- This is certainly specific to the N54. The N20 should be similar in effort, but will have different parts and locations will be different. I've not done this on an N20/N26 yet.
Just planning for the future. Is there a recommendation on a bullet proof water pump? I’m reading it’s the electronics that go bad in these and not necessarily the plastic pieces on the inside. Are the plastic pieces not allowing the heat to “transfer”/escape whereas an all aluminum would allow more heat to escape?
I bought a Pierburg 11515A05704 - Full metal (including bolts) for my fix 2 years ago -- It's still good.
What the 11515A05704 actually is — and why it exists
BMW originally used VDO/Continental (A2C59514607) to supply the electric water pump for the N54/N55, and those pumps were plagued with issues. Pierburg released the 11515A05704 as a documented upgrade: improved aluminum housing design, quieter and more robust construction, higher-quality steel screws, integrated control unit, and lab-validated hot-climate testing. The e90post community forum has a thread literally titled "Pierburg full metal N54/N55 water pump (aluminum, revised board housing and bearing)" — meaning Pierburg itself iterated on this pump's board enclosure and bearing, which is almost certainly the source of the "rumblings." oembimmerpartsOEMBimmerParts
The part number supersession chain
Previous revisions include 11517563659, 11517588885, 11517632426, and 11519455978 — all predecessors that roll up into the current 11515A05704. Each revision addressed something. The current part is the most evolved version of this pump design. ECS Tuning
Failure modes being discussed in the community
The rumblings fall into two buckets:
1. Electronics/PCB failure — this is the big one. One N55 owner noted their pump died from electrical issues and pointed out this is the same architecture as the N54, and commented that internal electrical failure is arguably the most common issue, not plastic cracking. The brushless motor drive board lives in a hot engine bay and gets heat-cycled constantly. The Pierburg's aluminum housing is a major improvement over the plastic-nose VDO, but it can't fully escape the physics of electronics in that thermal environment. The e90post thread title naming "revised board housing" confirms Pierburg acknowledged this and made a fix — but there's no publicly available data on what batch/date the revision landed, so you can't know for certain which version of the board any given unit has. SpoolStreet
2. Bearing wear — the second item called out in that e90post thread title. Some units have shown premature bearing degradation. Also reportedly addressed in a revision, but same caveat about batch transparency.
3. Silent failure — the main downside of an electric water pump is that you may notice nothing — nothing except overheating, with no mechanical whine or visible leak giving advance warning. This makes it especially concerning on a car like your Z4 where the engine bay is tight and a thermal event is catastrophic. Turner Motorsport
What vendors say about lifespan
Across the board, the N54 and N55 engines are flagged as prone to water pump failure, with a 60,000-mile replacement recommendation regardless of apparent function. Turner, ECS, and others all echo this. That's not a knock on the Pierburg specifically — it's a statement about the fundamental design of electric water pumps in this application. ECS Tuning
The honest recommendation framing
The Pierburg 11515A05704 is still the best available option for this application — it's what the entire knowledgeable community (SpoolStreet, z4-forum, e90post) recommends over the plastic-nose VDO, and major vendors like FCP Euro sell it with their Lifetime Warranty, which signals they consider it reliable enough to back. SpoolStreet members describe it as "both OEM and better than OEM at the same time." spoolstreet
But it's not bulletproof, and you should know:
What the 11515A05704 actually is — and why it exists
BMW originally used VDO/Continental (A2C59514607) to supply the electric water pump for the N54/N55, and those pumps were plagued with issues. Pierburg released the 11515A05704 as a documented upgrade: improved aluminum housing design, quieter and more robust construction, higher-quality steel screws, integrated control unit, and lab-validated hot-climate testing. The e90post community forum has a thread literally titled "Pierburg full metal N54/N55 water pump (aluminum, revised board housing and bearing)" — meaning Pierburg itself iterated on this pump's board enclosure and bearing, which is almost certainly the source of the "rumblings." oembimmerpartsOEMBimmerParts
The part number supersession chain
Previous revisions include 11517563659, 11517588885, 11517632426, and 11519455978 — all predecessors that roll up into the current 11515A05704. Each revision addressed something. The current part is the most evolved version of this pump design. ECS Tuning
Failure modes being discussed in the community
The rumblings fall into two buckets:
1. Electronics/PCB failure — this is the big one. One N55 owner noted their pump died from electrical issues and pointed out this is the same architecture as the N54, and commented that internal electrical failure is arguably the most common issue, not plastic cracking. The brushless motor drive board lives in a hot engine bay and gets heat-cycled constantly. The Pierburg's aluminum housing is a major improvement over the plastic-nose VDO, but it can't fully escape the physics of electronics in that thermal environment. The e90post thread title naming "revised board housing" confirms Pierburg acknowledged this and made a fix — but there's no publicly available data on what batch/date the revision landed, so you can't know for certain which version of the board any given unit has. SpoolStreet
2. Bearing wear — the second item called out in that e90post thread title. Some units have shown premature bearing degradation. Also reportedly addressed in a revision, but same caveat about batch transparency.
3. Silent failure — the main downside of an electric water pump is that you may notice nothing — nothing except overheating, with no mechanical whine or visible leak giving advance warning. This makes it especially concerning on a car like your Z4 where the engine bay is tight and a thermal event is catastrophic. Turner Motorsport
What vendors say about lifespan
Across the board, the N54 and N55 engines are flagged as prone to water pump failure, with a 60,000-mile replacement recommendation regardless of apparent function. Turner, ECS, and others all echo this. That's not a knock on the Pierburg specifically — it's a statement about the fundamental design of electric water pumps in this application. ECS Tuning
The honest recommendation framing
The Pierburg 11515A05704 is still the best available option for this application — it's what the entire knowledgeable community (SpoolStreet, z4-forum, e90post) recommends over the plastic-nose VDO, and major vendors like FCP Euro sell it with their Lifetime Warranty, which signals they consider it reliable enough to back. SpoolStreet members describe it as "both OEM and better than OEM at the same time." spoolstreet
But it's not bulletproof, and you should know:
- The electronics remain the Achilles heel, and the pump can die silently
- Buy from FCP Euro specifically for the lifetime warranty — if it fails, you swap it for free
- The aluminum mounting bolts are single-use — replace them every time the pump is removed Turner Motorsport
- Plan a proactive swap at 60–70k miles rather than waiting for failure
- On the N54, an ISTA+ query during a service can check whether the pump is reporting back correctly