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The battery light came on in my 2000 E39 while on the highway. After about 40 miles the lights began to dim, dash warning lights came on, radio shut down. I made it into my driveway just as the car died. I assume the alternator failed. There was a slight burning smell for a minute or so. The question is whether this did any damage to the engine or transmission. Nothing looks damaged or burnt.
 

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Older than old school
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You should be fine. Pull the alternator, have it tested then replace it should it prove bad.
OP, this has been others' experience. Check out Bluebee's account of her alternator failure.
 

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The battery light came on in my 2000 E39 while on the highway. After about 40 miles the lights began to dim, dash warning lights came on, radio shut down. I made it into my driveway just as the car died. I assume the alternator failed. There was a slight burning smell for a minute or so. The question is whether this did any damage to the engine or transmission. Nothing looks damaged or burnt.
One failure mode of the alternator is bearing seizure. If that happened and the spindle locked up, the pulley was not turning and the rubber belt might have been getting cooked. However, this same belt also turns the PS pump and water pump. Did you notice any loss of power steering or elevated engine temps? Be sure to check that the PS and WP units are okay. Regardless, you might want to replace the belt.
 

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Discussion Starter #6
Alternator

The belt looks ok but it can't hurt to change it. Has anyone had any experience with rebuilt alternators. I'm wondering if the cost of an OEM alternator from the dealer is worth it.
 

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You didn't mention if your car was an I6 or V8.....different alternators. You most likely won't be able to get the V8 water cooled alternator checked.
All of the ones you buy (doesn't really matter from where) will be rebuilt units.
4 days ago I helped a friend change his watercooled alt, it's about a 2 hr job if you haven't done it before and you have the correct tools.
He got it at Advanced Auto in Dorchester, in was stock, less than $400.
I changed mine about 3 years ago, the light came on and I could smell smoke. No other electrical things were damaged.
If you have an I6 it should be easier to change and less expensive, plus you can find parts to rebuild it.
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Also forgot to mention check fuse F15 and F18 above the glove box.
Replacement alts do come with a red tag that says to charge the battery like the others have mentioned below.
 

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Seek to understand,^Value
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Has anyone had any experience with rebuilt alternators
Very many of us put in rebuilt alternators - and some - the best - rebuild their own.

Read this thread, for example, to see a typical newbie experience (warning - it's from a newbie who never installed an alternator before - but that might be useful to you because of that):
- One users' example of total electrical failure (AAA towed away) alternator repair (1)


In addition, in the bestlinks, look for the word "alternator" and you'll find tons of good threads on what rebuilding entails:
- Aioros 1999 Valeo Alternator rebuild DIY (1) and quest for materials (1)
- DIY for replacing the brushes in an (Audi) Valeo alternator (1)
- Cn90 rebuild of 1998 Bosch Alternator for $30 (1) (2)
- Bosch 120 amp rebuild DIY for a VW (1)
- Cn90 explanation of why you want to rebuild your own alternator (1)
- Cn90 explanation of where to get hard-to-get alternator rebuild parts (1)
- How to tell from the part number if the alternator is rebuilt "by" Bosch (1)
- Bosch alternator bearing replacement from a 1997 MB S600 (1) & Range Rover (1)
etc.


You most likely won't be able to get the V8 water cooled alternator checked
Interesting statement.

I'm sure they can be checked on the car - but - I assume you're intimating they can't be checked off the car in the spinning machine because they can't be cooled?

Without knowing how long it takes to burn them up, can they be checked off the car sans water cooling for just the minute or two it takes to run the machine on them?

 

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DanQ, the liquid-cooled alternators on 540's are a lot more complicated than starters.
 

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Interesting statement.

I'm sure they can be checked on the car - but - I assume you're intimating they can't be checked off the car in the spinning machine because they can't be cooled?

Without knowing how long it takes to burn them up, can they be checked off the car sans water cooling for just the minute or two it takes to run the machine on them?

No it's not the lack of water cooling that's the problem. AutoZone's cross reference hook up book for the water cooled alternator calls for them to use cable #xxx?? which doesn't connect to this alternator. He looked at every connector he had and none of them fit.
He then told me they couldn't test them.
 

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He looked at every connector he had and none of them fit.
Interesting.

We should probably document WHICH cable part number they need so that OTHERS can avoid this problem (especially if they need to borrow transit while the alternator is out).

If we can get someone to report the cable number needed, folks can CALL AHEAD to ask if they have it in their drawers.

For example, here is a screenshot from my alternator thread showing an Autozone part number 12281 and a cable adapter N-09 needed for my 120 amp Bosch air-cooled alternator.

Note: I'm not sure what the "12281" indicates - as it could indicate either the alternator or the cable - I can't tell from my picture below which it applies to.


Here is a picture of the actual cable he used for my Bosch 120A air-cooled alternator:


And, in his machine, he had these cables:


And these adapters:


So that others can simply call ahead in the future to see if the right cables are in stock, the question we'll need the next person to answer for the water cooled alternators is what cable and what adapter number does Autozone use?

EDIT: I opened the following thread just now to get that table filled out by the tribe:
- If you have your alternator tested at Autozone - please tell us which cables/adapters
 

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You didn't mention if your car was an I6 or V8.....different alternators. You most likely won't be able to get the V8 water cooled alternator checked.
All of the ones you buy (doesn't really matter from where) will be rebuilt units.
4 days ago I helped a friend change his watercooled alt, it's about a 2 hr job if you haven't done it before and you have the correct tools.
He got it at Advanced Auto in Dorchester, in was stock, less than $400.
I changed mine about 3 years ago, the light came on and I could smell smoke. No other electrical things were damaged.
If you have an I6 it should be easier to change and less expensive, plus you can find parts to rebuild it.
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Also forgot to mention check fuse F15 and F18 above the glove box.
Replacement alts do come with a red tag that says to charge the battery like the others have mentioned below.
Thanks for posting this, JimLev. I have a feeling I may need it in the next year or two. Thanks also, Bluebee, for bringing it up in the other thread. I had overlooked it here.
 

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The battery light came on in my 2000 E39 while on the highway. After about 40 miles the lights began to dim, dash warning lights came on, radio shut down. I made it into my driveway just as the car died. I assume the alternator failed. There was a slight burning smell for a minute or so. The question is whether this did any damage to the engine or transmission. Nothing looks damaged or burnt.
How many miles did you have on it?
 

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If it spins smooth, just buy the new voltage regulator and put it back together. The regulator has new brushes in it. This is a very easy job, and you can take it back to AutoZone and get it checked again. I did this the end of the summer, and have had no issues since.

http://www.ebay.com/itm/BMW-E39-E46...Parts_Accessories&vxp=mtr&hash=item20be15a1b2
Yep, 50 bucks says it's just worn brushes. Get the right voltage regulator for whichever alternator you have, if you go this money-saving route. Plus the cost of bearings (replaced yourself, too), you'll have a mostly rebuilt alternator for way less than half the cost of a rebuilt unit.

The mid-priced alternative to buying an already rebuilt unit with exchange is to take your alternator to a local automotive electrical shop and have it rebuilt and returned to you. It will always be cheaper than paying a middle-man.

Brett
 

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my alternator just died 4 days ago, horrible burning smell/noise, and not charging. obviously the bearings went bad. i bought a remanufactured one through RockAuto for a good price, i will let you know what the quality is like. 2001 540i/6 (water cooled)
 
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