New alternator help

So the red battery symbol has shown up on my 2000 528i and my car has started dying alot. What alternator replacement should i get? is there any deals or can i do something else like a rebuild or something?

I have had bad experiences with alternators rebuilt by Bosch, i.e. noisy brushes or bearings; One would not even rotate right out of the box. More recently, I have had good luck with rebuilt alternators from Pep Boys.

how much did they charge? did the work on it take long?

Search forum for "alternator rebuild" using:
* New bearings x2 ---> $50 for both bearings
* Voltage regulator (HUCO brand) ---> $55

Look for posts by:
"Takechan"
"aioros"
"cn90"


This way you know you get quality alternator.

The rebuilt alternator from local autoparts store is usually a crap-shoot as people take short-cut when rebuilding alternator these days. Very often you end up trying 3 different alternators before you get a good one.

Type /alternator into the bestlinks and you'll get, among others:
- How to test your generator (1) & how to determine exactly what alternator you have (1) & a DIY for replacing the E39 I6 alternator (1) (2) (3) (4) (5) or E39 V8 alternator (1) (2) (3) (4) & why you want to clean out the air-cooled alternator air duct & cooling vents (1) (2) (1) (2) & why rebuilding an alternator is preferable to replacing (1) & cn90 DIYs for rebuilding a 1998 air-cooled BMW Bosch alternator (1) (2) or his VW Bosch alternator (1) & cdawg246's quest for materials for a Bosch water cooled alternator rebuild (1) & Aioros' 1999 Valeo Alternator rebuild DIY (1) and his quest for materials (1) & Cn90's explanation of where to get hard-to-get alternator rebuild parts (1) & how to tell from the part number if a replacement alternator is actually rebuilt "by" Bosch (1) & a DIY for replacing the brushes in an (Audi) Valeo alternator (1) & a Bosch alternator bearing replacement from a 1997 MB S600 (1) & from a Range Rover (1).

Originally Posted by Rob13567

how much did they charge? did the work on it take long?

Did it myself in about an hour and the cost was around $250 for the part.

I would get a Bosch rebuilt. I dont know of any other brand that would be better.

Bosch rebuild alternators these days are a crap shoot.
As I mentioned above, some people have to try 3 diff alternators before getting a good one.
This tells you something: rebuilders take short cut and do a bad job rebuilding the thing and sells it to you for $200-$250.

Rebuilding an alternator is so easy, I don't know why people don't do it more often.
Two (2) bearings and a VR and you are done.
The only special tool you need is a gear puller ($10-$15) to pull the bearing.

So how much do you spend in total rebuilding your alternators cn90? and where can i get the gear puller at? and is it really that easy because i dont wanna mess up my car.

Go through this post by "Takechan", and click on the links I posted in that thread:

http://www.bimmerfest.com/forums/sho...d.php?t=668350

Thank you, much appreciated

I got a rebuilt Bosch from Rock Auto for $117. It is working fine.

Wife was a little nervous regarding the $ downside of a failure on the road as the car 98 528i has 150k miles on the clock so I did a preemptive changeout.

Ned

Are we SURE you need a new alternator? Sure it's not a new drive belt you need?

BH

I had mine rebuilt at a local starter/alternator shop for $127. It has a 2 year warranty.

Back in the 1980s and 1990s, I used rebuild Bosch alternator all the time, zero issues.

For the last 5-10 years, the quality of the rebuilt alternator has gone down a lot (do a google search and you will see). My theory is they use short-cut or using Chinese parts etc.
Just when you think you put a good rebuilt alternator in, it fails 6 months later.

Considering that the laternator is a crucial item (whn it fails, you are stranded), I take no chance.

This is why when you rebuild it yourself, you know for sure you put quality parts in there:
- Bearings x2
- Slip rings are optional.
- VR: stick to Bosch or HUCO and nothing else.

Originally Posted by barneyhyphen

Are we SURE you need a new alternator? Sure it's not a new drive belt you need?

BH

how would i check? the car is 13 years old with a bosch 120a

Maybe you just need to clean it? Debris overtime can get lodged in there and block airflow to cool it. I also agree, rebuilding it yourself would be better than gambling. It's also cheaper. This all depends on how much down time you can afford.

Serpentine belt. just start up the car, open the hood and look down the front of the engine, between the engine and the radiator. There's a long 3/4" wide ribbed rubber belt, driven by the crankshaft pulley at the bottom of the engine, which drives the water pumt, alternator etc. also travels around an idler pulley/wheel and tensioner pulley/wheel.

If this belt breaks, the alternator will stop working immediately, along with the water pump and, if you drive long enough, with it broken, the engine will overheat and you will blow the HG.

Good luck with your fix.

BH

Originally Posted by barneyhyphen

Serpentine belt. just start up the car, open the hood and look down the front of the engine, between the engine and the radiator. There's a long 3/4" wide ribbed rubber belt, driven by the crankshaft pulley at the bottom of the engine, which drives the water pumt, alternator etc. also travels around an idler pulley/wheel and tensioner pulley/wheel.

If this belt breaks, the alternator will stop working immediately, along with the water pump and, if you drive long enough, with it broken, the engine will overheat and you will blow the HG.

Good luck with your fix.

BH

The belt looks fine, I've noticed with a multimeter that the battery is at 14 with the car on but when off it slowly starts to drain below 11.75 when off for couple hours( i have no amps, speakers etc completely stock) and the red battery symbol is lit, which i read in the manual means alternator problem.

Is the meter showing 14v at the same time the red battery light is on?

Must be honest, if I were getting 14v across the battery, whilst the car's running, not sure I'd run straight to thinking i had an alternator problem.

However, I think I might take the alternator out, pop the end off and at least clean it thoroughly with some electrical component aerosol spray cleaner. Can only help. Could perhaps be a VR problem in the alternator internal wiring?

could it actually be a battery problem, rather than an alternator problem? How old is the battery? Do you have another battery you could briefly swap in?

Good luck.

BH

Don't by chance have a power steering fluid leak from one of the PS hoses under the PS reservoir? They have a tendency to leak all over (into) the alternator. Such could very likely cause VR problems inside the Alt'

BH

Originally Posted by barneyhyphen

Is the meter showing 14v at the same time the red battery light is on?

Must be honest, if I were getting 14v across the battery, whilst the car's running, not sure I'd run straight to thinking i had an alternator problem.

However, I think I might take the alternator out, pop the end off and at least clean it thoroughly with some electrical component aerosol spray cleaner. Can only help. Could perhaps be a VR problem in the alternator internal wiring?

could it actually be a battery problem, rather than an alternator problem? How old is the battery? Do you have another battery you could briefly swap in?

Good luck.

BH

What is a VR problem? The red battery is only lit when I turn the key to the second position without turning on the engine.and the alternator is completely clean. Here is a pic of the battery

Sent from my SCH-I605 using Bimmer App

The battery light should be on if ignition key in 2nd position but engine not running.

You don't have a problem.

BH

From your description above, your alternator is fine.
However a battery reading of 11.75V after a few hours of rest means that you have either a bad battery or a parasitic drain problem.
See Bluebee's best links thread in the stickies on page 1 of this forum for help on diagnosing both.