N55 / N54 Water Pump Failure (Complete Walkthrough!)

[Estoril240i]

Hi all,

I want to share this experience in one concise post in an effort to help others when this inevitably happens to them. This is what happens when your water pump fails, how to diagnose it, and fix it. Consider this a (SOLVED) thread.

The car: 2012 135i N55 83k miles, DCT, 98% stock.
The issue: Water pump failure (Electric coolant pump failure).

How the problem began: The water pump turned on (noisy whirring sound) when unlocking the car prior to turning the car on. I could hear it begin to whir as I approached the car from a distance. After turning off the car, locking it, and walking away, the water pump would continue to run for a few minutes. This problem persisted for about 2 weeks until it inevitably failed and fell silent. Additionally, the oil level sensor would no longer send a signal to the iDrive, and would not monitor oil level.

How the problem continued: One day I unlocked the car and noticed the silence. No more water pump...I fired the car up and it immediately threw the “Engine Malfunction, reduced power” iDrive warning and the yellow engine signal light. The car began to misfire so I limped the car home. The next day it struggled to turn on and stay on.

How I fixed the problem: The codes read the following:
378F: BSD: Electric coolant pump: missing
3446: BSD: Oil condition sensor: missing
332E: Terminal 87_1: No voltage
38A4: BSD: Intelligent battery sensor (IBS): missing

Notes: I learned through this experience that when the water pump fails, it kills off most of the BSD system with it. Our N54/ N55 water pumps fail approximately every 50-80k miles. To fix it, I replaced the water pump and thermostat with Genuine BMW (Continental) parts from Turner. When the water pump goes, it typically takes fuse number 11 (Terminal 87_1) with it, so I had to replace the fuse as well. Once complete and with new coolant, the car runs like new. In total, this job requires approximately two afternoons in an average garage/tools with a skill level of 6/10. Watch the videos below for more information.

I recommend the following parts:
(1) BMW Antifreeze Coolant - 1 Gallon T#1474 (82141467704)
(1) Thermostat - E82 E9X E84 E70 E71 with N55 engines T#360235 (11537601158)
(3) Steel Mounting Bolt for N54 N55 Water Pump T#35690 (11517602123)
(1) Genuine BMW Water Pump T#584787 (11519455978~OEB)
This can be purchased from most vendors as a kit:
“Genuine BMW Water Pump And Thermostat Kit - N55 3.0L”
T#: 557278 | Part#: (11517632426TKT)
(1) Optional recommended: BMW Coolant Hose - 11537545665

I recommend following these videos step by step:
https://www.youtube.com/watch?v=o-Bp...arianAutosport
https://www.youtube.com/watch?v=FeYC...arianAutosport

Additional Note: Some tutorials for the WP/TS recommend dropping the radiator fan and draining the radiator to provide more working space and less mess. This is optional and not something that I did. If you want a really nice clean and straight forward job with no bloody knuckles, you may want to consider doing this extra step. (See https://www.youtube.com/watch?v=g8qo...hannel=FCPEuro)

Once complete, clear the codes and fire the car up. This should be it! Leave your comments and feedback below. Let me know how this experience went for you.

[dtla1]

Thanks for the write up. I do remember hearing my water pump running maybe an abnormal amount some time ago, so it's very possible that is a key sign/warning sign of impending failure. Something I'll definitely keep in mind when listening to the car.

As far as the time it takes I think you're right. someone doing this in their driveway, for the first time, might take up to 6 hours or so with breaks, time to figure out how to get access, taking their time, not having the ideal tools (I still need to buy some flex head ratchets), etc.

[Samhuss786]

I am currently going through something similar, after i switch the car off there is an electronic noise coming from the engine bay which hangs around for a few mins, ive also noticed thT my oil level shows "inactive" and also, when my engine gets up to temp, it shows reduced power on idrive and the car shuts off, it will start again when i click the key out but will eventually switch off again... any ideas?

[Emanyankee]

Dude….

Thank you for this. Picking up an 08 with 130k next week that needs ofhg and I doubt the water pump was done recently…. So bound to fail soon! 🙃

[KaneOG]

Originally Posted by N55_135_2012

Hi all,

I want to share this experience in one concise post in an effort to help others when this inevitably happens to them. This is what happens when your water pump fails, how to diagnose it, and fix it. Consider this a (SOLVED) thread.

The car: 2012 135i N55 83k miles, DCT, 98% stock.
The issue: Water pump failure (Electric coolant pump failure).

How the problem began: The water pump turned on (noisy whirring sound) when unlocking the car prior to turning the car on. I could hear it begin to whir as I approached the car from a distance. After turning off the car, locking it, and walking away, the water pump would continue to run for a few minutes. This problem persisted for about 2 weeks until it inevitably failed and fell silent. Additionally, the oil level sensor would no longer send a signal to the iDrive, and would not monitor oil level.

How the problem continued: One day I unlocked the car and noticed the silence. No more water pump...I fired the car up and it immediately threw the "Engine Malfunction, reduced power" iDrive warning and the yellow engine signal light. The car began to misfire so I limped the car home. The next day it struggled to turn on and stay on.

How I fixed the problem: The codes read the following:
378F: BSD: Electric coolant pump: missing
3446: BSD: Oil condition sensor: missing
332E: Terminal 87_1: No voltage
38A4: BSD: Intelligent battery sensor (IBS): missing

Notes: I learned through this experience that when the water pump fails, it kills off most of the BSD system with it. Our N54/ N55 water pumps fail approximately every 50-80k miles. To fix it, I replaced the water pump and thermostat with Genuine BMW (Continental) parts from Turner. When the water pump goes, it typically takes fuse number 11 (Terminal 87_1) with it, so I had to replace the fuse as well. Once complete and with new coolant, the car runs like new. In total, this job requires approximately two afternoons in an average garage/tools with a skill level of 6/10. Watch the videos below for more information.

I recommend the following parts:
(1) BMW Antifreeze Coolant - 1 Gallon T#1474 (82141467704)
(1) Thermostat - E82 E9X E84 E70 E71 with N55 engines T#360235 (11537601158)
(3) Steel Mounting Bolt for N54 N55 Water Pump T#35690 (11517602123)
(1) Genuine BMW Water Pump T#584787 (11519455978~OEB)
This can be purchased from most vendors as a kit:
"Genuine BMW Water Pump And Thermostat Kit - N55 3.0L"
T#: 557278 | Part#: (11517632426TKT)
(1) Optional recommended: BMW Coolant Hose - 11537545665

I recommend following these videos step by step:
https://www.youtube.com/watch?v=o-BpUzAemyQ&list=PLs9MZ9QggTUH3aCNks43K5GJs9ZfYh9Et& index=1&t=688s&ab_channel=BavarianAutosport
https://www.youtube.com/watch?v=FeYC305quNQ&list=PLs9MZ9QggTUH3aCNks43K5GJ s9ZfYh9Et&index=2&t=17s&ab_channel=BavarianAutospo rt

Additional Note: Some tutorials for the WP/TS recommend dropping the radiator fan and draining the radiator to provide more working space and less mess. This is optional and not something that I did. If you want a really nice clean and straight forward job with no bloody knuckles, you may want to consider doing this extra step. (See https://www.youtube.com/watch?v=g8qozaA0PJU&t=1198s&ab_channel=FCPEuro)

Once complete, clear the codes and fire the car up. This should be it! Leave your comments and feedback below. Let me know how this experience went for you.

Do you think you could point out fuse 11 to me? I must be overlooking because I cannot find it anywhere. My belt ate the water pump wires and I fixed them and it works fine but I still have the terminal 87_1 code

[KaneOG]

Originally Posted by KaneOG

Do you think you could point out fuse 11 to me? I must be overlooking because I cannot find it anywhere. My belt ate the water pump wires and I fixed them and it works fine but I still have the terminal 87_1 code

I was able to find the fuse, however it was not popped. Back to troubleshooting

[tracer bullet]

Originally Posted by KaneOG

terminal 87_1 code

Do you have more info on it? Is there more to the code itself, what tool did you use to find it, etc.

[KaneOG]

Originally Posted by tracer bullet

Do you have more info on it? Is there more to the code itself, what tool did you use to find it, etc.

Here is a list of codes that come up through MHD. After I fixed the wires on my water pump I did have 1 code clear which was "water pump missing". These remain and I've checked all 20amp fuses on my fuse box.

[tracer bullet]

I see a bunch of O2 sensor codes. I'd find those guys and start tracking down their wires.

I'm definitely not an expert w/ the subject but - it just seems pretty clear there's something going on with them.

Sometimes a code will come up as a symptom of another problem, somethign the car decided to do, change, stop, or whatever. But these seem to be saying short circuit so - in theory it means those wires are tied together at some point.

You might also want to be 100% sure of the work you already did, make sure you didn't accidentally cross wires with each other, or work on wires that weren't the ones you thought they were.

[MtBMW73]

Older thread, I know, but just had my water pump fail (I think) and found this thread through a search. My 2013 E92 overheated and I have codes 3792 and 38A4 (along with 38B4 BSD: No message from intelligent battery sensor).

The IBS codes were there before the water pump issue. Any ideas if/how these two are related? How would the IBS affect the function of the water pump?

[tracer bullet]

Originally Posted by MtBMW73

The IBS codes were there before the water pump issue. Any ideas if/how these two are related? How would the IBS affect the function of the water pump?

FWIW I agree it makes no sense. Can't think of any way at all they'd be connected. That said, supposedly the water pumps tend to fail for their electronics (I can't confirm that) so... maybe, somehow there's a connection.

[MtBMW73]

Originally Posted by tracer bullet

FWIW I agree it makes no sense. Can't think of any way at all they'd be connected. That said, supposedly the water pumps tend to fail for their electronics (I can't confirm that) so... maybe, somehow there's a connection.

My car actually has no IBS -- I now recall researching this a few years back when I replaced my battery. Some of the E90s were never equipped with IBS (those without navigation/iDrive or telephone prep/BMW Assist did not get IBS). I have no idea though why it throws IBS codes when the car was never equipped with IBS.

So to your point, I believe the IBS code and water pump failure are unrelated.

[dillonblo007]

Good day everyone, i might have the same issue but i need ya’ll help,
I have a 2010 135i N55 Dct
When i bought the car, everytime i lock it or unlock it or even open a door, i hear the coolant pump turning on for a couple of minutes then it goes off again. I confirmed its the coolant pump because i checked in the expansion tank.
Now winter is coming and its starting to get seemingly colder, now when i lock or unlock it, the coolant pump doesnt switch on immediately it takes like a min or 2 then it switches on for a couple minutes and then switches off, i read a couple threads that its normal because it primes the coolant system and what not,
And i get error codes for the alternator, coolant pump and oil level sensor saying they are missing, so im not sure if this sound is normal.
Can someone maybe help me out with a answer here?

[tracer bullet]

Originally Posted by dillonblo007

Can someone maybe help me out with a answer here?

I think the sounds made after a door is opened (and the car hasn't been driven for a while) is the fuel pump priming?

When we get strange codes it often turns out to be a failing battery. The low voltage out of it seems to make everything else electronic seem like it's failed.