BMW E46 Alternator DIY (voltage regulator)

If you build the little tool I mentioned in another thread (24 mm socket, 10x50mm bolt, and a couple of washers), taking off the alternator is an absolute snap. Takes like 2 minutes, and the same thing for putting it back on.

All these people using crowbars, pick axes, and mallets to remove and replace alternators... I've got to believe this is way easier than trying to replace the VR while it's still on the car...

Originally Posted by acon

My main issue is that my alt has the vr with the oval connector instead of the rectangular connector as listed so after buying the rectangular one on Pelican I had to return it...

Same here. Seems some E46 models built in 2003 have a 120-amp alternator more commonly associated with the Z4, making it rather difficult to find the relevant VR. If your alternator has the oval electrical connector/plug noted above on the rear of the alt., then you need the VR with Bosch part number F00MA45219. (The 2nd & 3rd being "digit zero," not "letter O.") That number is not easy to come by -- make a note of it if you have the relevant alternator.

As of this writing, Pelican sells it for $65 but it doesn't cross-reference to the E46 and you won't find it on their site. You must call with the Bosch number above.

I am just about to attempt this on a 2002 325Ci, does anyone know if this car has the bosch or the valeo? Also I was looking at the regulator on partsgeek and it shows 2 different regulators that appear to be the same thing, does anyone know the difference between the top 2

http://www.partsgeek.com/catalog/200...regulator.html

I get about 11V while the car is running, and about 9V when the car is off, but the battery is dead. No noise from the alternator, so I'm pretty sure it is just the regulator.

Originally Posted by Chris3Duke

If you build the little tool I mentioned in another thread (24 mm socket, 10x50mm bolt, and a couple of washers), taking off the alternator is an absolute snap. Takes like 2 minutes, and the same thing for putting it back on.

All these people using crowbars, pick axes, and mallets to remove and replace alternators... I've got to believe this is way easier than trying to replace the VR while it's still on the car...

Chris: Please forward the thread you speak to regarding the "little tool".

Originally Posted by yemff

I am just about to attempt this on a 2002 325Ci, does anyone know if this car has the bosch or the valeo? Also I was looking at the regulator on partsgeek and it shows 2 different regulators that appear to be the same thing, does anyone know the difference between the top 2

http://www.partsgeek.com/catalog/200...regulator.html

I get about 11V while the car is running, and about 9V when the car is off, but the battery is dead. No noise from the alternator, so I'm pretty sure it is just the regulator.

When I replaced my voltage regulator in my '02 325ci, in order to find out whether I had the Bosch or Valeo VR, I had to remove the air intake box, as well as unbolt the PS reservoir and put that to the side (it can probably be done without having to worry about the PS reservoir but it made it a little easier and it's two simple bolts so why not). Then, I got my iPhone 4 (thank goodness for the LED flash, I never thought that thing would ever come in handy...) and tried angling it where the VR was (I'd say that this requires some dexterity, and even then, expect a whole lot of trial & error) and by luck, after taking countless photos with my iPhone 4's camera, I was able to find out my VR was a Bosch 120A. You can probably do the same with a small mirror (key word: SMALL) but regardless of which way you choose to find out which VR you have, that's the way I decided to go about with it.

Hope this helps!

Originally Posted by filipinoise

When I replaced my voltage regulator in my '02 325ci, in order to find out whether I had the Bosch or Valeo VR, I had to remove the air intake box, as well as unbolt the PS reservoir and put that to the side (it can probably be done without having to worry about the PS reservoir but it made it a little easier and it's two simple bolts so why not). Then, I got my iPhone 4 (thank goodness for the LED flash, I never thought that thing would ever come in handy...) and tried angling it where the VR was (I'd say that this requires some dexterity, and even then, expect a whole lot of trial & error) and by luck, after taking countless photos with my iPhone 4's camera, I was able to find out my VR was a Bosch 120A. You can probably do the same with a small mirror (key word: SMALL) but regardless of which way you choose to find out which VR you have, that's the way I decided to go about with it.

Hope this helps!

that does help thanks. So was that all you had to remove to replace the regulator? or did you have to remove the fan or anything like that. It seems to be a pretty tight fit in there.

Ok I just took the regulator out, it was pretty easy. The hardest part was trying to find what size socket to use. Once you get the air box and the power steering reservoir out of the way there is plenty of room.

Originally Posted by tractioncircle

I just replaced my the voltage regulator Bosch 120A on my 02 325i.
Some information on testing the alternator diode pack (Rectifier) that might be useful to someone diagnosing the alternator.

1.> Once you remove the cover from the alternator, you will see six soldered terminals around the back of the alternator. These are obviously the stator windings ends.
2.> To test if your diodes are ok, you need to put your DMM (multimeter) in the diode test mode ( -|>|- ) symbol.
3.> Touch one DMM lead to the soldered winding end and the other to the long bolt (The alternator output, B1+) terminal. This will either give you '1' or some number (I got 436) that is the voltage drop across the diode in mV. Reverse the leads, the readings should be reverse of what you got earlier. i.e. if you got a '1' before, you will get some number now and vice a versa.
4.> Repeat this test with all the six exposed soldered ends. In each case the the reading should reverse. if you get same reading in both directions, You have a failed diode and your alternator will be putting out AC voltage.
5.> Now repeat this test with the smaller bolt coming out of the alternator.
6.> Again repeat this test between the alternator body (ground) and the winding ends. You should get the same results. Same reading in both directions from step 4,5,6 indicating a failed diode inside.

DO NOT DO THIS WITH THE CAR RUNNING. DISCONNECT THE BATTERY +ve while doing this.

This will tell you if you can get away with just changing the regulator or not.


Thanks Again!

Can anyone clarify this? Especially what the stator winding ends are, I dont see 6 of anything on the back of the alternator, here are the best pictures I could find if someone can point out these winding ends to me

http://www.e46fanatics.com/forum/sho...d.php?t=635777

Maybe some of you want to save even more! I have been reading a lot, and the price is just too much for a penny pincher like me. My car sometimes will charge for just a second if I rev the engine. So I do think that it could just be the brushes in the Alternator. I see that you may be looking for the brushes! So I'll not only include the link to buy them from, but also a PERFECT video tutorial by this guy who sells them. Please buy those one's as I believe they are being sold by the video man himself. Very professional, and it's because of him that I'm writing this post.


THE VIDEO ^
http://www.ebay.ie/itm/150797624638?...T&_trksid=p398
THE BRUSHES ^

Thanks for the posts about alternator repair. It was a huge help to me! I thought I would return the favor and post my experience.

I have a 2003 330CIC. I had just replaced the battery and the dash light indicating "no charge" came on. After checking the E46 Fanatic posts, I figured either the alternator or volatage regulator was crapped out. Checking the battery with the car running indicated ~11.5 VDC....nothing at all was coming from the alternator!

I followed the other posts guidance and had the alternator out in no time. I do think it is easier to pull the fan assembly, both belts, air cleaner box, and leave the power steering reservoir in place. The only real headache was the bottom bolt with the "sliding nut" that was very frozen in place. You can see this nut in the pix (a captured rusty look nut). A pry bar was needed to free it. Be sure before re-assembly to tap this nut out a little with a piece of brass or something so as to gain some clearance when putting the alternator back in place.

Anyway, after getting the alternator out, the bearings sounded fine when hand spinning and the collector rings looked OK (not great but OK)...see pix. The alternator also passed the "smell test". If the windings get hot, the varnish burns off and has a distinct "electrical" smell.

A quick check of the diodes indicated they were fine. Although not comprehensive, you can check them with the diode setting on your DVM. Remember there are two sets of diodes (forming the full wave rectifier), see my crude drawing also in the pix. Three diodes are between the common ring to ground and the other three are between the common ring and the battery. The common ring is the "bent piece of heavy wire" connecting all the diode pins. All (when forward biased) are facing the battery. Again, with your DVM set on "diode check", check across the common ring and the diode, when forward biased they should be reading ~.4 VDC and when reversed biased they should read "open" or "OL". Change the bias by changing the position of your test leads. Red to black, forward biased and vice versa. Again, see pix.

If the bearings look good and the diodes check out, it is likely the VR. I ordered mine from Autohausaz.com for $42 and some change (Bosch OEM). Even after shipping, I was under $50!

After getting everything back together, I had 13.4 VDC on the battery when running. Life was good and the beemer was back on the road.

Again, thanks to all that posted and I hope mine will help someone a little!

H all, wife has a 2002 valventronic e46 96000km on it, got red battery symbol on/off in the space of 3 days, one afternoon car wouldn't start at all.

Got a jump start & drove fine, NO red symbol, next a.m started fine again NO batt.symbol, but being blinded by everyone its the battery its the battery and not reading posts here we got a new battery....

After new battery red symbol came on, revved up engine and it went away and we drove on monitoring it, few hours later it would come on every 200-300 meters.

So we decided to take to mechanic same day on the way there NO red batt light came on...!

Mechanic could see via his OBD diag too that at the time we had red batt symbol even with new battery about a 10v charge was coming off alternator.


He has replaced the regulator and the spinning part he called the clutch that had some play it it up and downwards and a wheel that was making squeaking noises (sorry poor nomenclature, not idea what technical names are)....and will see how it goes

But what are the other parts that can go wrong?, can the the actual core of the alternator cause this erratic issue, and I swear about a year ago when we Batt.symbol was again on and off and then had the EML light come on , and eventually car went into limo mode 2 times, we got crankshaft and camshaft sensors, ignition coils, sparks and engine flush and oil change, ccv tube replaced we had no issue at all for a year....

Sounds like the voltage regulator getting ready to go. My car had similar intermittent battery light until I accelerated hard one day and it stayed on. Luckily I was close to home. If mechanic replaced the regulator you should be ok. You probably won't see a battery light again.

Only other thing to check would be to make sure the ground and battery cables are tight. Mechanic likely did this though.

Originally Posted by Sixracer

Sounds like the voltage regulator getting ready to go. My car had similar intermittent battery light until I accelerated hard one day and it stayed on. Luckily I was close to home. If mechanic replaced the regulator you should be ok. You probably won't see a battery light again.

Only other thing to check would be to make sure the ground and battery cables are tight. Mechanic likely did this though.

six racer thanks we had the regulator replaced and all so far after a day, but he gave me the old regulator and the box of the new one, and the part numbers don't tally! basically the old one stamped F 00M 145 285 that cross refs with part number 12317523059 on the realoem site looks like it is for use with 120/140a alternators but correct me if i am wrong please anyone as I am not sure I am reading the realoem table correct

http://www.realoem.com/bmw/showparts...48&hg=12&fg=22

BUT the one he replaced it with is for use on a 150a alternator
Voltage regulator 150A 1 04/2002 part number 12317540656

If he got the regulator into your alt, you're fine, I'm sure. I'm not an electrical engineer, but I suspect this part is pretty generic.

Use your cluster test (see youtube vid by SolidJake) and see what voltage you're getting with car off and on...should be around 12.2-5V when off and around 14v when on.

HTH

If it fits, you are good. I am an engineer and more "A" the better!

6racer and dmax all seems fine so far and part fitted fine, will also do the cluster test and see, but the realoem site really threw me......with regards to parts perhaps being super ceded with another part number, anyway have added chart again just to make sure what I had before and what i have now wont burn my car to an ash, also dmax can i use a good old fashioned digital multimeter across the battery terminals to check the volts rather than fiddle around to find the obc settings for it....?

Updated the first post with the nut sizes.