Yet another alternater....
 

Well, the alternator bearing is going yet again. It seems like I am replacing the alternator every year and a half. This has been a real thorn in my side for a while. I can't let the car sit for more than a couple of days or the battery will be dead. It seems as though I have a parasitic drain on my battery. I have checked all the light bulbs (and the trunk) and they all go out okay. I went so far as pulling the fuses last year and checking the amperage drop. (the car sits at about .8 amps at parked in off after resting for 5-10 minutes) That might be considered a bit of a parasitic drain but not really that extensive. ?I usually replace the battery every second alternator (pathetic eh?). Th alternator never fully charges the battery. I recently cleaned the connections at the battery because the were somewhat sulphated. That didn't make much of a difference. When I step on the brakes the headlights dim a bit. The charging rate is at about 12.5 volts. It should be at 14 at least. This kills me. I can never get an alternator to last in this car and charge at 14 volts. 125 amps should be enough for it. It is stock. Anyone have any fixes for this or similar problems?

I would suggest changing you Alternator supplier. Sure, it's a good thing that you may have a Lifetime Gaurantee, but failures this often are a bit extreme. I can't offer much help in the battery drain dept. As a last resort you may want to consider a Quick-Disconnect attached to one of the battery terminals(Positive, I would guess). The bad news here is you would constantly lose all your radio presets and time.

I have bought from 4 different suppliers already. The way that I see it is this. Maybe there is a parasitic drain. The alternator is not charging properly but still running hard. Something running at 100 percent duty cycle fails early (especially bearings). As far as having a quick disconnect, that is really not an option because of the adaptive learning of the PCM. Having to go through a new learning cycle every time I start up would cost me a fortune in fuel. Any more suggestions?

I kind of have same problem. My battery runs great at day time, but at night when i turn lights on and wipers and system the battery kind of has some problems. I think my alternator is not chargin at full. Plus some times when the car is at stop it kind of wants to turn off and than the alternator powers it up and it works ok. like it has short brake ups. Hmm?

The night time thing has been discussed almost to death here, especially since it's winter and we use a lot more of the electrical.

This is normal. Someone even posted a tech article from GM stating that the volt reading should drop when at idle with several accessories going. Unless you are dipping all the way into the red, then it's a "feature" not a "bug".

My plan to solve this is to give DeathRat some money this spring and upgrade to a 160 or 200 amp alternator. From what other members have said, this will solve the bearing problem, and by my own theory, the bouncing voltmeter.

As far as your drain, I have no idea what could be causing that. Almost anything could potentially be shorted out. The only way I'd know to test it would be to have someone start pulling fuses, while someone else watches the meter. When it stops, you at least know which circuit to follow.

DP carries heavy alts as well.

Check battery cable bolts for corrosion inside plastic/rubber cable ends.Check for clean and tight connection where negative cable bolts to engine block. Are you sure the bearings are going in the alternator?A bad diode can result in unbalanced field condition resulting in loud whine that could be mistaken for failing bearing,hence electrical problem.I had a loud whining Delco alternator on my last Buick .On a cold engine the alternator case was hot enough to burn my hand within about a minute.The intake manifold was still cold .It wasn't the bearing.If it is bearing failure consistently then I'd be looking to belt tension problems or maybe incorrect (too short ) belt.Finally ,have a starter amperage draw test done.Voice of experience here again.A defective starter may start the engine normally but suck the battery so low in that brief time that the alternator goes full output trying to recharge it. I think my alternator went first,then discovered the bad starter,and shortly after replacing starter the battery went.For replacement starters and alternators I'd put AC Delco reman parts or NAPA's best (Rayloc?) or equivalent at the top of my list.Carquest used to carry quality reman components also.I wouldn't touch auto chain store lifetime warranty stuff.Rather have a quality part I replace once than a lifetime supply of junk.Good luck

how can I tell if it's the battery or alt? just last night when I went to warm up my car I noticed by voltmeter was very low (almost in red zone) it doesn't get that low unless im running the rear defrost, left from work last night and almost made it home when all my information was flashing on and off in my electronic display. Could the battery cause this? I really don't want to buy another alt right now.

mista sse, you probably would get more attention to your car's problem if you posted a new topic instead of appending to a current topic.That said,if it were me I'd drive to Autozone and ask them to to check my battery and charging system.It's still free as far as I know.

just a little followup on starters and alternators.My understanding is that AC Delco themselves do not remanufacture these items but are contracted out where they must be reman to Delco's high standards.A while back I came across an article about this on the "Idavette" (Idaho corvette club) website.They compared AC and Bosch reman components by teardown and inspection/measurement.About 3 years ago I needed an alternator for my Lesabre.The parts man I know at Pep Boys said not to get the cheaper Prostart rebuilt because they last about 11-12 months before the bearings fail.They're only warranted for 1 year so you may or may not get warranty replacement.He recommended the more expensive totally 100% new never rebuilt one's with lifetime warranty as they weren't coming back.I got one and it lasted 21 months and 21000 miles.I asked him what the" track history" was on these now that they've carried them for a few years.His answer: about 24 months.It was working fine when I sold the car but my next alternator will be AC.Here Advance Auto carries them as well as a few other local stores.