Charging sys lite on for few min after start

[Babyhauler]

02 w/ 198,000 on it now had the charging sys lite come on for a few min yesterday & today. Put my meter on it & it was the same as the guage, 12.xx. Correct for a battery properly charged. After a few minutes it slowly moved up around 14 or so where it always runs, both guage & meter. Today, it did not do it cold, but did it later after a 20 minute stop. I turned on headlights, ac and everything to see if that would affect it. It did not go down or make any different noise as if using jumpers on a dead battery. It ran a minute and climbed back up where it should be. I read several post about the newer trucks alt. computer controlled system causing fluctuating readings, but mine is an 02 and never done this.

 

I'm guessing the voltage regulator is trying to die.

 

Another issue that might be related is an awful squeaking sound when cold and never really went away after it was warm. That has been going on for several months. New belts did not help. I never could isolate or feel where the sound was coming from.

It did not squeak yesterday or today. Weird. Any ideas?

 

Babyhauler

[dewfpo]

Re : Squeaking. When you changed the serpentine belt did you check the idler pulley's or the tensioner pulley for smooth rolling, noise or wobble/looseness. Often when a pulley bearing goes it makes a 'whining' noise that is often affected by temperature or alternator draw.

 

Re : Charging circuit. Once the engine is started the alternator should be putting out 14.5-14.7 volts within a few seconds and then coming down as the battery gets re-charged. You can have your battery load tested for free at most auto-parts chains. As well they can test your alternator/voltage regulator. Most places just sell you a new alternator when the diodes in the VR start to go bad.

 

DEWFPO

[Babyhauler]

loud squeaking, Loud enough for wife to notice. pulley bearings previously disassembled, cleaned & re greased. Smooth as new. Put a wrench on everything a while back just to check. Bought new pulleys friday to change out this weekend. Just in case and now this. Took belt off previously & started for a moment, no noise from ac components.

 

Probes on alt show 14.xx volts after minute or so of 12.xx untill it decides to start charging again. Only happened several times sat & sunday. No issues with battery or starting yet. Battery about 7 months old. I do not know if problem would duplicate on alternator machine. Do they have a way to check it on vehicle? It may develop a pattern & I can get it checked.

Thanks

Babyhauler

[waumo1]

Every GM alternator of that vintage I have owned failed long before that mileage. You need a new one.

[Babyhauler]

Yep, I thought it was dead. Monday, once hot, it went for 10 minutes or so before charging again. I still would like to know what part was dead.

I bought a reman GM unit from the local GM parts dealer. Went ahead and replaced the belt pulleys & bearings. Something squeaked quietly for a minute this morning & stopped, never heard it again all day. Maybe that newer belt is the cause of the noise. The harmonic balancer is about the only thing not new under there. Not much stuff left to change.

Thanks for the help.