Alternator Bosch or OEM BMW

Yes. I had one on my e39 (M54) for a long time. Probably put close to 75k miles on it before I sold it. It was the Bosch variant. No issues with it at all. In fact, it appeared to be a Bosch reman in an Autozone box. Hard to tell what the internals were but they looked exactly the same.

If anyone is curious, the 120a Bosch and Valeo alternators (rectangle ground connection) are completely interchangeable despite the statements online saying they have different pullies and mounting points. They are slightly different but everything lines/bolts up the same. The Bosch (left) is a decent amount larger in size, not sure why, but it fits perfectly with no clearance issues.

The forums are riddled with people who tried to save a few bucks & got what they paid for. The DME on an e90 is extremely fickle. DO NOT buy an alternator unless it\u2019s a Bosch.

Volvo tech here, Bosch. Just replace the whole thing, it's not worth doing the brush job only to find that you should've just done the whole thing first.

I ordered the genuine Bosch alternator for not even 300 bucks and installed it myself for him still good a year or so later and it was a very easy job

Get the Bosch, including the warranty from them, and be done.

13V is normal for a stock Bosch alternator. There are 14V or adjustable voltage regulator available as a replacement.

Im having the same issue with my 08 jetta 2.5, replaced the alternator and voltage regulator because the car battery wasnt charging anymore. Anyways replaced the alternator and then I had a high voltage issue with the regulator

I had a bosch alternator in my Mark 2.. 8valve motor. I noticed the battery was not being charged. so instead of dealing with the voltage regulator or brushes etc, b/c the unit was old I decided to go with a brand new one.

I when my original alternator failed in my 540i/6, the replacement rebuilt Bosch unit would produce 13.5-13.7v for a while after the car had warmed up, then would gradually fall to less than battery voltage. Running the A/C and revving the engine at stoplights would keep the battery light from flickering, but eventually, it would show full symptoms of a dead charging system.