valeo alternator / inconsistant voltage

[tim96]

i have a valeo alternator in my e30 320i. On some drives it works fine but other times my all my lights strobe e.g voltage goes up and down up and down. Bad voltage regulator i suspect? belt is tight could anything else cause it is there a way to test it. I put a volt meter across the battery and the voltage is nt constant so i guess it is the regulator (12.5 - 15.5v) for memory not sure but it did reach 15 +.. volts
Reading around on the forums this is easy to change on the bosch alternator but i cant find info on how to change the voltage regulator in the valeo

or is it better to just replace the whole alternator? if so would a bosch alternator fit?

[witeshark]

Some auto parts stores will do an electrical check for free. My first guess it the voltage regulator.