Re: alt or batt?

Most likely it's the alternator, the battery doesn't usually cause the battery light to come on when driving. You should be able to tell with a voltmeter on the battery terminals with the engine running, should be in the

14-volt range with the engine running above idle. If it's down in the 12-volt range, your alternator's not working.

We haven't had an alternator go bad since we started doing the same thing, only replacing after 5 years. Here's what usually happens:

Old battery won't hold a charge, voltage is low but enough to start engine.

Alternator produces a lot of current to charge it.

Rectifiers (diodes) in alternator fry and go bad.

Replace the alternator.

Replace the battery.

1 Vote for battery 1 Vote for alternator 1 Vote for both

alternator (10

As old as the battery is, I'd change that 1 first, but be ready to replace the alternator, too, as a 10 year-old Saturn alternator is getting pretty old.

The simplest test is testing the voltage while it's running (mentioned before). Odds are if the alternator is bad, the 5 year-old battery is about gone, too.

Ken

My battery is now over 6 years old. Was fully drained once in its first year. Car bought in June 1997. What are my odds I'll make it through the winter here in Toronto?

Frank

97 SC2 123k km Original battery

After 5 years I would say you need a battery. The problem may not be the battery right now but replace it before it leaves you stranded. It is also a lot easier to replace than the alt..

When you go to buy the new battery go to someplace that will test the alt. for you. If it tests fine then put the battery in and your done. If not buy the alt too.

I put a new alt. in a few years ago and it was not fun. ('95 sw2)

Good Luck, Jeff

Tenzo wrote:

Depends a bit on your philosophy:

Myself, I'd change the battery, the alternator and since you have it off, the serpentine belt. You do it once and its done for good.

Let us know what you do and the cost. For me, the works came just under US $300 for top of the line components.

Frank

97 SL1 98,600Mi

Sounds to me like the problem lies within the alternator right now. The idiot light is a simple thing that grounds out when the alternator is not charging(to turn on the light). But since the battery is so old I would replace that too, moreso now that you've run it dead.

Unfortunately it turned out to be both.

Post mortem appears;

Battery leaked acid and the alternator broke trying to charge a disabled battery.

Course they also found that it needed a new belt, retensioner, points replaced and positive battery wire was carodid so it had to be replaced. When I saw that they wanted $179 for the damn cable I just got the battery and alternator.

How can it be that much for a damn battery cable?

$500 for battery and alt.

alternator

Is that just for parts?

Ken

This gets me thinking. I knowwhen I disconnect the battery on my '93, there's a little sparking and all going on. I know the replacement baqtteries we've put in were always rated a bit higher than the OEM type.

Now, it seems to me there's a bit of vehicle off current draw. Maybe what's killing everyone's alternator isn't a bad alternator, but a big surge when recharging the battery that the alternator's a bit small for? Not to mention the running load - is there a difference between the failure rates of alternators in stick and automagic cars? Mine's stick and only popped one in 200,000+ miles

The current draw is from things with always-on microcontrollers and memory backup. Like the radio, engine control computer, car alarm, etc.

Measure the current with a multimeter. Last time I tried it was very low, don't remember the number now.

Jim

Thats a good point. Mine's a stick and the only one I've broken in the 95k miles I've owned the car was my own fault......much less than what people make it out to be.

I've seen rebuilt alternators shipped ( for the Saturn S-series ) with a note attached to the alternator warning that failure to charge the battery before putting the new alternator into service may cause premature failure. My guess is they can't take the combined load of charging a low or dead battery and running the car. The two I've blown happened after the vehicle sat for an extended period of time. ( 2 -3 weeks while I was out of town ) At about 95k on a 95 SW2 and about 135k on a 95 SL2. Both are auto trannies. I wonder how many blow shortly after the owner gets a jump start and drives away with an uncharged battery ?

My 1998 SW2 is a stick and I'm on the original battery and alternator after 94k miles. I'll probably replace the battery before winter comes.

-DanD

That's why I asked it :)

I'm starting to think the alternator isn't the culprit here. Yes, I know the behind engine location is 'supposedly' bad (though I've never seen temperature readings for both on top and behind locations), but I seem to recall that the Saturn was one of the first cars with an electronic tranny (was Chrysler's Ultradrive the first?), and having a few solinoids in there adds a load even if they are just little pilot types working the valves body. And another computer, etc etc etc.

Given the popularity of automatics, a difference in failure rates sure would make it 'seem' that the alternators are weak. And we know transmission shifting troubles are often a sign of impending alternator doom...

Very good points. Like you say.......since the majority drive automatics it would 'seem' that the alternators themselves are the problem. Maybe there is another cause.

Regardless though, the alternator installed in the vehicle should be tough enough to withstand the stress that is put on it by that vehicle.