shamrode

I took my car for a fast long tough drive. After about an hour the red battery light came on and the radio turned off. I kept driving and when I arrived home I checked the charge which was 11.3 volts (too low.) My question is which part of the alternator is not working properly? Is it the voltage regulator, the alternator itself or perhaps the pulley bearings? Is there any way to diagnose this? Can the pulley go bad and be replaced without taking apart the alternator?

Jasonoff

Did any of these threads help?

https://mbworld.org/forums/c63-amg-w...ase-chime.html

https://mbworld.org/forums/c63-amg-w...lternator.html

https://mbworld.org/forums/c63-amg-w...behaviour.html

https://mbworld.org/forums/c63-amg-w...r-battery.html

This one is my favourite
https://mbworld.org/forums/c63-amg-w...-question.html

https://mbworld.org/forums/c63-amg-w...lp-please.html

https://mbworld.org/forums/c63-amg-w...or-output.html

zcct04

^ A really good example of how powerful the search function is here. Jasonoff works it like a ninja.

Newbies - take note and learn from the master!

shamrode

Nope. Didn't really help but thanks. My main question is and remains "is there a way to tell if the pulley bearings are ok." We have a very complicated energy management system on our cars and with complicated you need excellent diagnostics as opposed to "oh change the battery."

sinape62

Well, if you're already come to the conclusion that something is wrong with the alternator, there could be several things that I could think of: brushes, VR, rotor bearings.

First, how many miles does the car have? Assuming this is the original alternator on a high mileage car, brushes are probably worn. I've changed brushes on another car I had with 183,000 miles, it had similar symptoms as you described.

shamrode

100k km. If it's the rotor bearings may it be felt physically checking for looseness

Jasonoff

Yank it and have it tested.

shamrode

Couldn't find a good thread with the exact how to's. I already took out my engine once and can't afford to again.

Jasonoff

It's not difficult. Once the panels underneath are removed it's easy to see.

First thread I shared, 2nd post explains how.
https://mbworld.org/forums/c63-amg-w...ml#post6426914

4th thread I shared, 6th posts links to a pic of the alternator location.
https://mbworld.org/forums/c63-amg-w...ml#post6080725

QWKSNKE

Pulley and bearings do not cause the alternator to not charge. It's going to be the stator, brushes, etc (something electrical)