Bad voltage regulator- anything else?

[Rtheriaque]

Thursday morning my '89 325i surprised me with two oddities. The battery (charge), brake fluid, and parking brake lights were slowly illuminating with intensity tied to engine RPM. No illumination at idle, fully lit by about 2500 RPM or so. This was accompanied by an awful whine from the engine compartment. Since I didn't install a supercharger the night before, I had to dig a bit deeper.

Voltage at the battery at idle was about 12.8V. At 2000 RPM I saw nearly 15V. Okay, bad voltage regulator. This is annoying as the alternator is a fresh Bosch-boxed rebuild for BavAuto with about 4,000 miles on it in 7 months.

So, my questions. Is the alternator simply screaming from overwork? Should I plan on swapping it as well as a precaution or just start with the regulator? Are there any other components known to fry from excess voltage that should be proactively replaced, or should I just keep an eye on things once I have proper system voltage again?

As always, thanks for your input, folks!

[jalopi]

alternators will whine when they're being overworked - but - a bad bearing can also create the same kind of whine (but infrequently).

[jeffnhiscars]

Rebuilds are known to fail and if its only 7 months I would think a warranty call to BavAuto is in order

[Quinthirty]

I just changed my voltage regulator a few months back and it was running at around 13+ with full load. Replaced the battery a month ago. I left the car for a week during the holidays and the battery went dead. When I checked the charge rate this morning, the voltage was only running at round 12.2 to 12.8?

I'm stomped. What else needs to be checked? Just replace the VR again?

[Rtheriaque]

What's the RPM during your test?

[Rtheriaque]

Just to expand a bit...

The first step here isn't to check the charging system. You need to understand the health of your battery and any drains when the car is off.

Start by looking for drains. With the car off and doors closed, remove the trunk light bulb. Set your multimeter to amps and disconnect the negative battery terminal. Connect the multimeter to the negative terminal and the now free end of your battery cable. This number represents your parasitic draw. Report back with that value.

Next, if you can, charge the battery and take it to a parts house to be tested. If not, at least check the voltage while somebody cranks the car. Let us know that number as well.