I have trouble sourcing the problem and was hoping someone could help.

Long story short, I recently noticed signs of the alternator not charging (there was NO WARNING LIGHT on the dash). Checked the voltage on battery with the engine running and confirmed there was a charging problem (12.2V)
I rebuilt the alternator- new regulator, brushes and bearings. Now, I read 14,5V which seems to be fine, but only for 1-2 minutes after starting the car. I also get intermittent BATTERY NOT CHARGING message even at the beginning when the alternator is charging properly. After 1-2 minutes the voltage drops to 12V.

Has anyone experienced anything similar or has an idea what might be the reason ?

Don't know if this is related, but at the same time I noticed lack of charging, a loud whining noise (my car is NOT SC) in the engine appeared ( hard to locate precisely). Suspected alternator bearings and then the water pump, but after changing both the noise is still present.

Any help would be much appreciated.

 

That noise sounds like failed diodes in the alternator .... If you turn on the radio can u hear a whine through the radio

 

Just checked that. No whine present, but this seems like a good lead. I think I'll remove the alternator and get a local shop to test it on the bench.

 

Check the 12v + where it connects through the false bulkhead. Poor connection.

 

Changing the diodes solved the problem. Thank you for your suggestion.