[sebsoja]

Hey guys, glad to finally be the owner of an E91, especially one with a 6 speed. The car I bought has around 170k miles with a great service history with a glaring hole - the water pump. To mine and the previous owners understanding, the car still has the original water pump and thermostat. What would be the bets course of action. They seem to fail spontaneously and wouldn't want that to happen on the upcoming 800 mile road trip or any ones in the future. Additionally, the previous owner replaced the battery but never programmed it in. It should be all good to just use my bimmergeek with protool to program it right? Thanks for the help.

[oVeRdOsE.]

Mine was original on my 167k miles, and I planned a trip, so Ive changed it to be safe. not super hard, but time consuming.

For the battery, we the k+dcan cable + bimmergeek app or a laptop with those bmw tools, and you'll be fine. Also check if the Ah of the battery match what is coded in the car.

[Efthreeoh]

Just scan the car with a BMW scan tool and check for the water pump codes. You don't say what year the car is. The pumps were improved in 2009. The thermostat does not leave the car stranded, just an emissions code appears.

[oVeRdOsE.]

Mine is a 2008, and when Ive asked on this forums if it can be the OEM pump, most people told me no.
So I had to call dealers where I thought the car was maintained, and no dealer had a pump change records.

so I did the job, and found the BMW logo with a 2008 date stamped on it.

The car was mainly winter driven, highway only and 6mt (no trans cooler to the rad). So might help on the pump

[Runnin'Rich]

The n54 turbo engines plastic pump is the one that is troublesome and leaves people stranded.

Like efthree said you should get a fault code stored to tell you it’s on its way out.

I too changed my n52 metal pump unnecessarily because of the n54 failure hype.

[lordnikon]

Originally Posted by Efthreeoh

Just scan the car with a BMW scan tool and check for the water pump codes. You don't say what year the car is. The pumps were improved in 2009. The thermostat does not leave the car stranded, just an emissions code appears.

It says 2008

[crashoverride]

Originally Posted by Runnin'Rich

The n54 turbo engines plastic pump is the one that is troublesome and leaves people stranded.

Like efthree said you should get a fault code stored to tell you it’s on its way out.

I too changed my n52 metal pump unnecessarily because of the n54 failure hype.

Actually the majority of the N52 had the plastic. Issues quickly became apparent and the N54 was improved and moved to metal.

The bad water pumps were installed in 2006 and were not used for long.

At 170k miles there is nothing to be worried about. The problematic water pumps failed in the 60k to 90k range. It either was unbeknownst replaced or got the improved redesigned pump installed day one. Not to say just like anything else that it cannot ever fail, but you are well beyond the pre-mature failure window time and there are literally 101 other things that should be fixed before this.


That being said the coolant system is one of the biggest weak points. The hoses fail prematurely and it's not a matter of "IF" but "When" the Mickey Mouse Flange will fail.

At your mileage I would check the belts and pulleys before a long trip. Do an oil change and check the brakes as brakes are an 80k mile or so you could be due soon.



.

[Efthreeoh]

Originally Posted by lordnikon

It says 2008

Not on my phone app...

[Efthreeoh]

Originally Posted by crashoverride

Actually the majority of the N52 had the plastic. Issues quickly became apparent and the N54 was improved and moved to metal.

The bad water pumps were installed in 2006 and were not used for long.

At 170k miles there is nothing to be worried about. The problematic water pumps failed in the 60k to 90k range. It either was unbeknownst replaced or got the improved redesigned pump installed day one. Not to say just like anything else that it cannot ever fail, but you are well beyond the pre-mature failure window time and there are literally 101 other things that should be fixed before this.


That being said the coolant system is one of the biggest weak points. The hoses fail prematurely and it's not a matter of "IF" but "When" the Mickey Mouse Flange will fail.

At your mileage I would check the belts and pulleys before a long trip. Do an oil change and check the brakes as brakes are an 80k mile or so you could be due soon.



.

A lot of what you said is not accurate. The N52 pump has always had an aluminum impeller housing. The early N52 used an aluminum thermostat that was later switched to a plastic housing. The N52 WP fails because the control electronics overheat. BMW has updated the N52 WP several times since 2005. The newer pumps do not fail from overheated electronics.

The N54 uses a plastic impeller housing, which tends to crack, then fail (leak). As far as I know only the aftermarket switched to full aluminum impeller housing for the N54.

I agree with the flange, it can fail due to age and heat cycling. Swapping to an aluminum flange is good practice for any N52 this far past E9X production end in 2013.

[Efthreeoh]

OP, if your car is a 2008 at 170,000, it may either have an improved pump electronics design, or failed years ago and was replaced. I also have a 2008 N52 in my Z4. The car is 16 years old and 120,000 miles. It has never shown a water pump trouble code. I've owned the car since 2014 at just 23,000 miles. There really is no decisive data that predicts when an N52 pump will fail. How long did the PO own the car?

[sebsoja]

First owner had the car until 2011 and then the previous owner bought it. I'm thinking along the same lines as you

[sebsoja]

Originally Posted by crashoverride

Actually the majority of the N52 had the plastic. Issues quickly became apparent and the N54 was improved and moved to metal.

The bad water pumps were installed in 2006 and were not used for long.

At 170k miles there is nothing to be worried about. The problematic water pumps failed in the 60k to 90k range. It either was unbeknownst replaced or got the improved redesigned pump installed day one. Not to say just like anything else that it cannot ever fail, but you are well beyond the pre-mature failure window time and there are literally 101 other things that should be fixed before this.


That being said the coolant system is one of the biggest weak points. The hoses fail prematurely and it's not a matter of "IF" but "When" the Mickey Mouse Flange will fail.

At your mileage I would check the belts and pulleys before a long trip. Do an oil change and check the brakes as brakes are an 80k mile or so you could be due soon.



.

Brakes have been fully redone within the year luckily. Ill do an oil change and take a look over in the engine bay before the trip. Any other suggestions? New to e90 ownership.

[sebsoja]

Originally Posted by oVeRdOsE.

Mine was original on my 167k miles, and I planned a trip, so Ive changed it to be safe. not super hard, but time consuming.

For the battery, we the k+dcan cable + bimmergeek app or a laptop with those bmw tools, and you'll be fine. Also check if the Ah of the battery match what is coded in the car.

Sounds good, thanks.

[StradaRedlands]

If no codes, don't be in a hurry. But when you do decide to do it, plan on doing the hoses, expansion tank, and radiator at the same time. Something will break somewhere in the process. Also the MMF and plan to do the OFHG. None of these are particularly hard or expensive, but they all loosely work toegether in one big system and when one needs replacing, the others likely do as well in my experience.

[Efthreeoh]

If anything to consider preemptive for replacement pre-trup is the Mickey Mouse Flange. You just have to drain about 32 ounces of coolant to get the coolant level below the head. You can then remove the t-stat hose at the head where the flange is and remove the flange from the hose. Replace the flange on the head side, then reattach the hose to it. It's an easy repair.

The beauty of the N52 with an electric water pump is bleeding the coolant when the engine is cold. Pour in some new coolant and bleed it. There are numerous DIYs on how to swap out the MMF. (cough-cough, I posted a good DIY on the MMF a few years ago).

[GoRomeo]

Correct you dont want to wait till 220k miles without changing your mickey mouse flange like me ☝️😂

[POBEP]

Originally Posted by sebsoja

New to e90 ownership.

Welcome to the community!
Congrats on the 6MT E91 !

Originally Posted by sebsoja

Any other suggestions?

Full tank of gas, adjust tire pressure and enjoy it!

---
Perhaps for SoCal car I would check if upper radiator-2-expansion tank hose is factory.
If so - replace BEFORE your trip or keep a spare in the trunk.
You do not need to drain coolant or bleed for this one.
It can leave you stranded and will create a mess under the hood when exploded
---
My E91 is 2009.
~10y ago I was told that WP must be replaced ASAP
I asked for specific codes - got nothing.
Fast forward at 15yr & 112K mi, still factory WP/Thermostat.

MMF came out as bunch of small pieces during OFHG replacement ~4 years ago.
MMF fails when you pull its hose out. It should stay in place otherwise.