DIY: 2003 E39 540i Auxiliary Water Pump R&R

[TheAngryBear]

My Aux Water Pump has been throwing intermittent codes and during my last coolant expansion tank swap it would work for 90 seconds then fade out. Time for an R&R. Uh oh, Bentley doesn’t have the procedure, nor does Pelican, or the other usual suspects. So here is my submission.

Vehicle: 2003 540iA Sport
Mileage: ~175k
Item replaced: Auxiliary Water Pump
Cost: $460 (FCPEURO)
Time: budget ~1 hour (took me 2 between pics, write up, and stopping two fights between the 5 and 4 year old)

Disclaimer: do this at your own risk, no fault of mine if you break something, damage your ride, can’t get this to work on your vehicle, have differing parts, cause a war, lose your dog, or any other action(s)/item(s) as a result of this procedure.

So first things first, what are we talking about?
http://www.realoem.com/bmw/enUS/show...diagId=64_0994
Item 1: Water valve with additional water pump, 64118374994

Here is the label of the part I used:


Where is it specifically on the 540i? Right side of the engine bay on the strut housing. Here are some pictures with zoom.



Here are the tools you are going to need:

Required:
Screwdriver (I used 7 mm)

Optional tools:
6 mm socket (if original or previous R&R put the hose clamps on weird you might not be able to access with a screwdriver)
Extension
Hose clamps (qty 3, only if you aren’t going to drain your cooling system)
Flashlight (if no adequate lighting)


Procedure
Sort of a pain to get access so take of the cabin air snorkel and acoustic cover.


Then you can clamp the hoses. Why clamp? So you don’t have to drain the cooling system.


Note there are three hoses, I clamped the other in front.


Your choice of order to disconnect the hoses, electrical, of the water pump. I did the valve electrical connection (1), then top hose (2), then pump hose (3), then pump connection (4), then bottom hose (5).


The unit lifts out of the top grommets. Nothing to it, honestly no other bolts, pins, etc.
Here it is without the pump there:



Let’s see if anyone can guess which is new vs old:


Put the new one in, reconnect hoses and electrical. Don’t forget to take the clamps off.


Bleed your system, check for leaks, and call it day.



Sent from my iPhone using Tapatalk

[HoZy]

If you're not afraid of a little more tedious work & don't want to spend excessive amounts of $$$ You can rebuild your own heater valve assembly including a new seal for the AUX pump which will allow you to clean it out.

https://www.ebay.com.au/itm/BMW-Heat...53.m2749.l2649

Cheers
Mat

[JimLev]

Nice write up. Wow $460 for a pump and valves.
If your old pump motor still works you may want to get the rebuild kit that HoZy linked to. Rebuild yours and sell it to recoup some $.

[philly98540]

Yes, good write up!

My pump stopped working a couple years ago, but I balked at the price. I took the motor apart and bought some generic brushes for $5 to replace the worn out ones. PIA job actually as it a bit hard/tricky to re assemble the motor. The valves and seats still looked good though surprisingly. Maybe my waterless coolant is helping?

Again nice write up.

[HoZy]

In regards to the "If you aux pump is good"

From memory, You can also purchase one of the cheap non-aux heater solenoid assemblies like

https://www.ebay.com/itm/HEATER-CONT...AAAOSwz3lZeBEw

And transfer the solenoid housing (The top) and the sleeve & seals from the base into your unit.

That's just another cheap way around an excessive heater solenoid assembly cost.

It's really all down to how much work you're willing to put in and how large your wallet is.

Personally, i did the seal kit from Ukraine, took 3 weeks to arrive and i did it while it was still in the vehicle.
I unscrewed the solenoid bodies and removed that to work on out of the car and i pulled the sleeves and did the bottom seals in the car.
(It sucked to do the bottom sleeves and seals in the car. But It meant not removing hoses, just clamping them.

Cheers
Mat

[TheAngryBear]

Thanks for the feedback!
I saw the rebuild kits but wasn’t interested in doing that. But with this info and having it out... JimLev may have the right idea... if nothing else a nice spare.


Sent from my iPhone using Tapatalk

[DiamondJQuimby]

Yes, good write up!

My pump stopped working a couple years ago, but I balked at the price. I took the motor apart and bought some generic brushes for $5 to replace the worn out ones. PIA job actually as it a bit hard/tricky to re assemble the motor. The valves and seats still looked good though surprisingly. Maybe my waterless coolant is helping?

Again nice write up.

I tried to do this on mine and couldn't even get the pump apart. It's super frustrating because it should be a really simple rebuild and I'll be damned if I'm going to spend $500 on the stupid thing.