Alternator or power regulator change at e64 2005 [Archive] - Bimmerfest - BMW Forums

: Alternator or power regulator change at e64 2005

BMW645 Germany
02-05-2012, 10:27 AM
Hello, did someone already changed the alternator or regulator? When I lay under the car it looks very tide. My Voltage always change from 12V to 13.7V very seldom stable. Sometimes I start and drive I read for a while 12V, it is not charging at all. Then suddenly it goes to 13.8 or 14V as like nothing been before.
So I guess the regulator need to change, its the cheaper part, so first try.
In the net I don't find something about the change.

02-05-2012, 02:40 PM
If you have access to an oscilloscope you can test the alternator first.
Looks like there are two different alternators.

Instructions for alternator 1. (
Instructions for alternator 2. (

Also google for 550i alternator DIYs. They are almost identical.

BMW645 Germany
02-05-2012, 04:25 PM

it look like I have alternator 1. So far easy, but the guy wont come out, I could tilt it to the right side but no movement out, something is still holding it. I do it carefully not to break something. For me would be enough to reach the Voltage regulator so I didnīt remove the fan cowl with electric fan. To tilt it later forward to remove the regulator would be enough.