Red Battery symbol, then abs dsc please help

[dabenthusiast]

Thanks alot. The obc works alot better then having to check volt meter.

New battery at stop is 12.4 and with it running I'm at 13.7
With headlights and heater and radio on.

Am I good or do I need an alternator??

Actually I assume I do.

I started to rev the car. And when it goes above 2k rpm the red battery light came on, then goes off below that.

After raving acouple times voltage dropped from 13.7 to 12.7 then I turned lights and heater again and revved and it went to 11.7 volt....

Give me the bad news

[puddinboo]

if alternator is working, it should be putting out consistent voltage not erratic, should be a steady voltage like around 13.8 v .nothing lower than 13v. (thats with the engine idling or and revved up.

[StephenVA]

The voltage fluctuation is a classic example of a failing regulator or the lack of contact of the slip rings and the brushes, which in turn drives the regulator to fail.
Volt flux is a sure sign of alt failure that only gets worse. Tests are done at idle, should read over 13.5 volts and again at 2500 which should show an increase to >14.0v.

Quick test, with one eye on the voltage, bring the rpm to 2500 hold, tap the alt with a soft hammer and see what if any change.
At anything over 85k I would remove the alt, while checking for worn or frayed wires. If your plans are long term ownership buy new, if not buy reman AFTER making the seller test the unit before installing. Some remans are slow to break in and provide full output volts/Amps. As mentioned before some models have water cooled others are just air cooled. When you lay underneath your x you will be able to tell.
Good luck.

[Ricky Bobby]

^Follow all of Stephen's advice, and I would personally go with a new alt - sooner than later in order to not fry that brand new battery

[puddinboo]

or screw up electronics in the x5 ,just incase the alt puts out power surge.

[dabenthusiast]

Originally Posted by Ricky Bobby

^Follow all of Stephen's advice, and I would personally go with a new alt - sooner than later in order to not fry that brand new battery

Cool ya that is my plan.
Now my problem is if I should get lifetime warranty from autozones new duralast alt.
Or new napa bosch style.

I don't think it is watercooled. Might you know @RickyBobby
If yours and mine are the same ?

And either way can i buy bosch or Valeo type or do I need to take mine out to verify then go buy one?

[Ricky Bobby]

^If you move the PS reservoir out of the way you should be able to easily see the type of alternator you have, Bosch or Valeo - pretty sure the 3.0's have Bosch's but you should double check -

[Joshdub]

I don't think m54s ever came with water cooled alternators

[dabenthusiast]

Originally Posted by Joshdub

I don't think m54s ever came with water cooled alternators

That's what I thought. Sucks for the v8s haha

Well I'll check. It's been raining in the bay area the past couple days.

Alternator is all from in the hood no under the car??
I'd so I'll work in rain buto I don't want to get on the wet ground ha

[Joshdub]

You can do it all from above. Takes about 45 minutes. Remove fan/shroud, remove airbox and intske pipe up to the rubber elbow, unbolt power steering res and move it to the side, undo belt, undo two alt bracket bolts, rear wire retaining nut, unclip wiring harness on back of alt, then pull it up and out in between engine and coolant res.

Easy peasy. Don't forget to disconnect the battery.