My poor old Subie wagon had a belt squeak; then it broke. New one started squeaking soon after. Then 2-3 weeks ago I needed a jump, and on the way home, at night, started missing--I killed the headlights, then the parking lights too, and barely had enough e-juice to fire the plugs and get home--3+ miles. On a posting that day was a procedure for checking battery and alternator. Sure enough, alt. was putting out less than the battery (recharged), checking across the bat terminals-- almost 13 not running, just over 12 when not. Got a rebuilt alt. and seemed to be fine. Then 2 days ago, again stumbled, had to kill the lights, etc--happily only 1 mi from house. AGAIN the output of the alt, measured terminal to terminal, running, is less than the recharged bat. by itself (not running). IS THERE a separate regulator that might be bad, as it seems unlikely that the alt could fail in 2 weeks. Is there some other component/situation I am ignoring? OR is there a fault with the battery that could be doing this--it's sealed so I can't do a fluid check (but it's not anywhere near new). I can keep a charge on it with the trickle plug-in, and get to school to drop or pick up the kids, but don't dare take a long trip--esp at night. (My alternative, the 914, is an almost daily driver, but now we've had a small snow-ice event that salted some streets. It has rained off, but more coming. Last item--still intermittent, sometimes ongoing belt squeak. I've replaced both, pulleys seem free when the belt's off (may not be free-spinning under tension--don't know). Tried to work some oil in at bearings of pulley. Still squeaked until I shot belt conditioner on the belts. Then it quieted, but started squeaking again in a couple of minutes. I want to get the old wagon back to usable before long--help! Thanks for any ideas, Chris

I would certainly suspect the new alternator, but maybe the belt is slipping because of an alignment or idler bearing problem. I would certainly check the juice going into the battery posts and the battery terminals to make sure that it is the same when the car is idling (at least 13.6, if not the same the terminals and cables need cleaning) and then check the battery to negitive ground and block to chassis ground and alternator to block ground and clean them all after removing and inspecting. If the charge rate does not come up the alternator (which has an internal regulator) is bad and it is just the luck of the draw that you got two bad ones in a row. If the battery was bad then the charge rate would be good but the battery would not hold it.

I agree with the Doctor.
Do this.
With car running, at idle, read volt meter accross battery terminals.
With car running, at 3500 RPM, read volt meter across terminals
With car off, read voltage across terminals.

It should be like this
13.6+-
14.0+-
12+

I have been amazed at how bad alternator rebuilding has become, so certainly bring it back.
The regulator is built it.

Rich

Keep in mind that it IS possible for a bad battery (or bad battery connection) to kill an alternator. It's also possible for a bad battery to pull the output of the alternator way down to the point of the car not running (but the battery would get very warm).

All kinds of possibilities. Bad battery, bad grounds, bad cabling, etc. You need to be methodical and go through the whole system. Charge the battery fully and get it load tested, test each cable connection for voltage drops (it's better to measure voltage drops across ground junctions than to try to measure resistance - do it with the lights on), get a shop to put your alternator on a scope and verify it's OK. Belt must be adjusted properly, no slipping.

A fully charged battery that's had its surface charge removed (5 min with engine off and lights on) should measure 12.75V. Any less means it's not fully charged, at 12.2 V it's only 50% charged, and at 11.9 V it's dead. Rich Towle's voltages at idle and at 3500 rpm are what your system should be delivering.

Thanks for taking a shot, guys. I trickle charged it for a day, drew it down for five minutes, and it read about 13.0 not running. On, at high-ish idle (1200) it read about 12.5, as it did at 3000 rpm. So either it isn't putting out a proper charge, or something else in the car is giving it trouble. Can I try starting it, then running it with hot battery un-hooked, and then check across from battery cable end to ground? Or any other test w/battery out? The gen. belt is very clearly the one that squeaks, which suggests that, like the old generator (maybe very old--I got the Sub used 5 years ago), somehting is putting up a big reaistance to spinning. Any other guesses?

remember that even if the alt. is showing a charge it is possible that it it not producing enough amps for the loads (lights,Radio,etc) You need to get it tested under a load. If you bought the Alt. at a autzone or simular store I would expect it to be bad thats why they give you such a great warranty

Do not disconnect the battery while it's running. The charging system uses the battery as a load, and if you take it away the voltage can go way too high. This can kill the diodes in the alternator, and even other voltage sensitive parts of your car, like the engine ECU.

Take the whole car to a FLAPS with a freshly charged battery, and have them test it. Most of them have a cart they'll wheel out to your car that can test the whole system. If they say it's the alternator, you can pull it out and they'll test it on a bigger machine. This is the only way to know for sure.

Check main fuses. On chevy, ford and chrys they would have a fusible link between the alt output and the battery. Nowadays manufacturers use a main fuse. If its blow you will only see battery voltage at the batt term when it is running.

Hi

You know, a couple things to think about...

We get bad "rebiult" alternators all the time, usually at the wost fuching moment.
But you HAVE to have your battery checked. I use a fancy gadget.
Bondo's words are bang on, bet you he's a tradesman
Stop pulling the battery terminals off while the car is running, this worked in the 60s, and even then.
I am sure the place you bought it from, would test the new alternator for you. It shouldn't be screaming the belt tho.... , is the belt slipping? or is the noise more of the alternator whining like a cheap whore?...

You know, a new battery is not a bad deal at 100$, to save you some headaches for the next couple years.

Keep us informed on the progress!
Good Luck
Later

No question that it is the belt. Belt dressing sprayed on the gen belt quiets it, usually only for a minute or less. Spraying the other belt (AC) does not quiet the squeal. Guess I'll ask the seller, a local chain, if they can test it. If not, I'll drive to a Flaps or whatever the equivalent here is. Thus far, through several weeks of problems, I have never tried pulling the pos (or neg) off the battery while running--and, with this advice, I certainly won't. I'll look into the fuse box for a big one out. And maybe switch batteries with one of my other cars to see if either vehicle changes with the swap. (yeah--tomorrow is supposed to warm up to 40. Then Mon we drop to highs in the 20s, lows near 10.) p.s.--My generator hooks into the rest of the electrics with a big plastic-covered bayonet plug, so I can't do any voltage test there, even if I knew a test to do at the gen output.)

You mentioned 13 volts without the engine running. Post the results of the battery output voltage with the engine off, and also with the engine off and the headlights on. Also avoid belt dressings, they treat symptoms, they don't solve the actual problem.

I just had a flashback to the underhood of our old GL-10 turbo. The fusible links are just to the rear of the battery, clipped onto a plastic tank. (windshield washer fluid maybe?) They're little loops of wire covered in colored fiberglass insulation. Check them out, I think there's 4 or 5.

Sun. was good--except for the Chicago line's poor performance, offense and defense. I wiggled the fuses behind the battery, and wire brushed the battery terminals and clamps; that got the running voltage up near 14. The belt squeel was pretty much gone if I left the heater on vent only; on heat, def, etc the compressor runs (second belt, not w/gen) and the gen belt squeaks again!. Set out anyway, on a 40 min. drive, and the belt broke half-way home. No problem, the bat. had enough juice to get me home. I'll get the new belt on later today (it's cold out there), and re-check the running voltage--and listen for the squeak, a mostly winter, almost two-year intermittent problem that has now claimed its third belt. (Fortunately new belts are cheap!) If the gen. resistance isn't doing it, maybe I need a new idler wheel--I squirt-lubed it last week (spins free under no load, no "feel" of bumpy bearings), but I might see if I can get it apart to be sure.) --At least I got the long-pending three plumbing jobs done last Fri--one had become crisis, w/water on the floor! More after the new belt is on.