Alternator Bosch or OEM BMW

Bosch has a support site that shows what alternators they recommend for your VIN number. AL20X (65A) and AL172X (65A) are the two Bosch shows. However most of us know the original was a 90A unit AL30X.

After getting mine rebuilt 3 times and still having the same problem, I ended up getting a Bosch factory rebuilt one. Cost-wise I don’t think it was significantly more than one rebuilt by a shonky auto electrician and in the long run would have been cheaper.

Had the same issue a few months back. Put in a new alternator and it’s been perfect since.

Mine was my alternator. Never had battery issues but once I replaced it with a new bosch all the electrical gremlins the car had went away.

Alternator wise, I'd definitely spend the money and acquire a nice Bosch unit to replace yours if you were gonna swap it.

You need to try using a OEM REMAN or OEM NEW alternator. Aftermarket items can really affect BSD.

I used to have an alternator that required me to rev to 5k before the light would go out! My current one needs a slight blip to 1200 to make the light go out. I just ordered a new Bosch rebuilt alternator to replace.

I want to replace the alternator myself, but I can't find where to get OEM parts for a reasonable price. The dealership is charging $340 for the part and the best I can find is this [Bosch alternator](https://www.amazon.com/dp/B001C64QHE/ref=wl_it_dp_o_pC_S_ttl?_encoding=UTF8&colid=TXMF4LHVIWCE&coliid=IN63F3OG0M77W) on Amazon which they state is new, but it seems like all Bosch alternators are remanufactured. Why is it so damn complicated to find high-quality replacement alternators?!

ended up going with a Bosch remanufactured alternator. Installed it today, went super smooth, charged up the battery as I was installing it, got everything buttoned up and started it up. Battery light still on, voltage is at around 11.9 and dropping. Will randomly jump up to 14.4 volts, no correlation with revving the engine or putting a load on the electrical system.

So I bought a new alternator off of Rock Auto that I was amazed that I had to re-use my old pulley? But when I went to put the pulley on, the nut stripped on the new alternator like instantly. The whole ordeal is trash