Alternator problem??
 

1991 325ix

I intermittently get what seems to be a voltage surge and my lights get very bright and blower speeds up. That's gone on for a while now, but very seldom. Last week it happened quite badly for an extended length of time and now my battery won't hold a charge.

I'm thinking it's the voltage regulator so I access the alternator and find it's the valeo 80A alternator. To get at the regulator I had to take the alternator out. When I looked at the regulator, it looked pretty worn, but I'm not 100% sure. I'd say it had 1/3" left. It's more difficult to find the VR for the valeo and it's costs about $65 minimum (pelican is out of stock).

Should I just buy a 90A bosch alternator and be done done with it?

Should I be confident that the regulator is the problem? Thanks.

Most auto parts stores have a alternator test bench and wil do a run test for free. You just have to remove it and take it in.

I have a Bosch on my 93, it stoped working and I took it to Advance Auto.
They tested it and it showed low output under load.

They gave me a price of around 300 bucks.

Turns out the brushes were bad. The brushes are integral part of the voltage regulator.
I found the assembly on line for around $30.

It is still on the car working fine.

Try this link, they have one for $27.

http://www.***************/search/product.aspx?sid=teu2ot55p0nywompdp2irs45&makeid=8 00003@BMW&modelid=1011935@325IX&year=1991&cid=18@E lectrical%20%26%20Vacuum&gid=4884@Voltage%20Regula tor

thanks coolbear. The regulator you linked is the one for the bosch though. It doesn't fit the valeo. My main question is: new regulator for 80A valeo for $70 or new 90A bosch for ~$170.

I apologise, I did not notice that you mentioned the fact that you hadd a Valeo alternator. I don't know enough about your Valeo alternator to answer your question. My experience is limited to Bosch.
But I will say, $100 more for a new Bosch, with a warranty sounds good to me.
They are easy to work on, and I have personally put alot of miles on them with no failures yet.
Other than a $35 VR that can be changed in 30 min..