I loaded the updates to my Foxwell today. No significant differences that I could see. The log said only change in the latest update was something for a Z3. I don't know if there were any updates between that one and the version I got when I purchased it a few months ago.

It was in the mid-50s when I started the engine and got the 4x4 light. DSC, ABS and TPF too after a few seconds, without changing out of Park.

After going into the gearbox data in the Foxwell, I saw 14.1 V at the battery but only 11.2 at the solenoids. That's the first time I remember seeing them being significantly different. This may be the warmest it has been outside where I've had the 4x4 and other lights come on.

I had popped the hood before starting the engine. I got out while it was idling and I didn't hear any obvious squealing sound from the belts.

One thing I noticed in the gearbox data was that all the "Level to L[n]" pins reported High except for L3. I don't know the significance of that.

After the oil temperature gauge was about half way up, I restarted the engine and all the warning lights went away.

My friend thinks it's the alternator. No belt slipping or squeaking.

Warmer today. 13 V from the new battery, just off the trickle charger. Dropped to 12.1 when I used the Foxwell in position 1.

Then, we got 11.8 V after turning the engine on. No error codes or warning lights this time, but it didn't rise above 11.8 V even after waiting until the oil temperature gauge was past half-way to operating temp. Same voltage at battery and gear box this time. Maybe 11.8 is barely enough to not error out the VTG, DSC, ABS and transmission modules, but still not right for proper performance.

Restarting the first time after warming it up this far didn't work either, still running at 11.8 - 11.9 V. Third time was the charm, immediately went to 14 V. That time, I used the dash Test 9, instead of the Foxwell. Probably not relevant, but noting it.

In good news, we also serviced my Stihl BR600 backpack blower. New filter, spark plug and cleaned the carburetor. Runs on the first pull again and idles better.

My friend's view is that it's better to replace the whole alternator because it's a relatively big job. Or is there an easy way to just replace the voltage regulator to rule that out?

I haven't seen any how to videos or write ups for the N62 X5 alternator or voltage regulator. I have the Bentley manual, but it doesn't go into detail that I've seen.

The engine runs great after it gets the proper 14 V and shifts are smooth after the transmission filter/gasket change and 3X fluid drain.


EDIT: Found this video which appears to be the N62

https://youtu.be/b8lobpyEldw (less than 14 minutes!)

A little hard to follow the commentary, but from what I can tell, he says you need:

- 10 mm socket for top brackets

- slot screwdriver to release clips

- T60 (release belt)

- 5/8" socket with breaker bar (16 mm?) to remove two bolts holding alternator to engine

- T50 (remove tensioner pulley)

- 13 mm socket to remove alternator after pulling it loose from engine

It appears he has removed the lower protection plate, but that doesn't seem necessary?

Yesterday it was a little warmer and I saw no problems on a trip across town. Around 14 V right away and steady round trip.

I found this thread which seems to be the problem I'm experiencing, though the OP's mornings were colder (around freezing):

https://www.bimmerfest.com/forums/sh...d.php?t=668157

The solution for him and a couple of others in the thread was replacing the whole alternator, though some suggested just replacing the VR may have solved the issue. Member upallnight is on that thread :)

One of the useful links is this video of replacing the brushes on the VR and cleaning up the slip rings on a Valeo:

https://youtu.be/aVvPzwtxdrM

I think I'm going to start with buying the VR and replacing. Removing the alternator seems straightforward based on the video I linked to in my previous post here. If the VR doesn't fix it, I'll replace the alternator. Opinions?

Questions:

1. Is there an easy way to disconnect the power to the alternator (remove a fuse, disconnect positive terminal under the hood, etc.), rather than disconnecting the terminals on the battery itself?

2. Realoem shows a different alternator for my 10/03 build than later models:

https://www.realoem.com/bmw/enUS/sho...diagId=12_1244

Do you think the Valeo regulator will fit both? (shows as fitting when I select my vehicle, but it's hard to tell if it fits both the -992 and -994 versions in the last two links below)

https://www.fcpeuro.com/products/bmw...eo-12318510090

The site shows two Valeo alternators that fit for me, but the first one shows up to 12/03, which covers my build:

https://www.fcpeuro.com/products/bmw...li-12317540992

https://www.fcpeuro.com/products/bmw...x5-12317540994

Use realoem.com and your ViN and it will show you part numbers specific to that particular ViN. Then go hog wild ordering from BMW and mention me as I'm apparently putting some German through a yacht financing course this month...[emoji857][emoji857]

Sent from my SM-A730F using Tapatalk

Thanks for the advice. The Voltage Regulator isn't listed or sold as a separate part on RealOEM, as far as I can tell. I did put in my partial VIN to get the page I posted previously.

I contacted this eBay seller with a great reputation. Their recommendation was to remove the alternator and check the part number on mine before ordering rather than relying on RealOEM or another site. I saw another poster who ended up with the wrong alternator by using the information there.

https://www.ebay.com/itm/100-NEW-ALT...A/271076047426 [probably the one I need by part#, doesn't list 2004 X5 ]

https://www.ebay.com/itm/NEW-ALTERNA...P/290786378197 [ only lists 4.8 for 2004 ]


Good luck with your parts adventure!

Definitely yes, get eyes on the alternator before you believe anything about what you have in there. Depending on how much time you have right now, you will probably be able to spend a few minutes removing the easy stuff above it, and can then get a camera down there to take a pic so you can read the brand or PN.

I have a Valeo 120A in my 06/2001 build 2001 3.0i. I bought a VR for a quick fix of the brushes problem, then bought the full rebuild kit from that guy in the youtube video, which I did about a year later.

You might find (and this would be the best scenario) that once you have the alternator out, you pop off the back cover and see that the brushes are worn down so one of them is barely in contact. Then you just replace the brushes or the whole VR and can be pretty sure you fixed the one and only problem. If you don't find that, it is less clear. And an intermittent problem like you have makes it harder to debug.

For my 2001 3.0i, Bosch and Valeo were used interchangeably. You can replace a Valeo that fits the 2001 3.0i with a Bosch that fits it. But the pulleys are different, so the unit as a whole is interchangeable, but no sub-parts are.

Thanks for the advice. I ordered the VR because it's the same one for both versions of the alternator in the 2004 N62. I also ordered the belt since it was only $13 at FCP Euro and qualified my order for free shipping, so only a $5 difference, in total.

My guess based on what I've read is at least one of the brushes isn't making good contact when it's colder or the sleeve is fouled enough that when it's cold the problem manifests. It could also be a diode probem as wpoll suggested.

The order probably won't be here until the first week of December, then I have to schedule the replacement with my friend. I'll update with the results when it's done.

Thanks for everyone's help so far!

a large voltage difference can be a ground or supply cable; the B+ cable has a disconnect at the jump point under the hood; several people have had a problem this year with that getting loose and causing voltages drops. The alternator feeds through that connection back to the battery.

when my alternator failed it was from oil getting into it and causing too much resistance on the fairly warn slip rings; i replaced the slip rings and brushes and it's basically good-as-new.

For somebody that just wants to nearly double the life span of their alternator; you could reverse the polarity of the armature slip rings and they will last nearly twice as long; only one of them wears (i can't remember which but with arc lamps it's the anode that gets beaten to a pulp so it's probably the - side (the electrons shoot across the gap from brush to slip ring) but i would have to measure to know for sure. I figured out a way to cut the supply bars and add some jumpers to reverse the polarity of the brushes ; i would love to do that on wife's alternator before the slip rings are too worn to help.

Thanks, Andrew. I'll check the cable. That's where I have my trickle charger hooked up. Its small cable sticks out at the edge of the windshield.

I'll disconnect the B+ cable when we replace the VR, to avoid an electrical mishap. I'm hoping I can clean any fouling of the slip rings rather than replacing them. With my low mileage garage queen, coming up on 41k miles, I don't expect they'll be too bad.

Interesting point about reversing the polarity. The video I linked to in post #33 showed the top slip ring fouled and the bottom one looking like new.

Since it's best practice to always remove the B- cable at the battery first, there's no need need to remove the B+. Just remove the B- at the battery and place it where it cannot contact the B- terminal on the battery, or wrap it in a rag etc. :thumbup: