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Which came first; battery grew a bad cell, or alternator overcharged?

Tiny
ALPHAA10
  • MEMBER
  • 1988 BUICK LESABRE
  • 3.8L
  • V6
  • 2WD
  • AUTOMATIC
  • 250,000 MILES
After parking my car at a store one hot afternoon, and returning to the car 30 minutes later, the starter sounded weak on restart.

After barely restarting the engine and making it home, I immediately opened the hood, and found the battery case was overheated and misshapen-- the lower battery case bottom portion actually swelled outward.

Despite my effort to cool and recharge the battery, I soon learned the battery had developed into a dead cell. With the cell cover removed, I found the charging current made every cell but one issue a tiny bubble periodically, which indicates a dead cell.

This four-year-old battery could have failed on its own, but that also suggests a failing alternator regulator might have killed the battery from chronic over-voltage during charging.

So, that is the question-- which could have come first, the battery bad cell or a bad regulator?

* PS-- Having a battery or alternator fail silently is a problem. To prevent something like this from taking me by surprise ever again, I plan to mount an alternator output voltage meter somewhere on the dashboard. Do you have any suggestions about this approach?
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Monday, August 28th, 2023 AT 3:47 PM

31 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,289 POSTS
Hi,

Since the battery is 4 years old, I suspect it failed internally. The idea that it was swollen at points can indicate overcharging, but oftentimes it doesn't.

So, here is what I recommend. If the battery has already been replaced, check the alternator output right at the battery. With the engine running, it should show around 14v.

Here is a link that explains how to test an alternator:

https://www.2carpros.com/articles/how-to-check-a-car-alternator

If it is over 15v, replace the alternator.

Let me know what you find or if you have questions.

Take care,

Joe
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Monday, August 28th, 2023 AT 7:31 PM
Tiny
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Thanks, Joe!
What do you suggest for long-term monitoring, to avoid, or at least deal proactively with either a (1) developing bad cell or (2) an alternator wandering off its proper electrical output?
If I permanently wired a meter to the alternator, that would tell me about the alternator output, but nothing directly about the battery. So, should I permanently connect the meter to the battery, instead?
Some LeSabre instrument clusters offer a voltage monitor. Is a battery-based meter connection the way some LeSabre voltage instrument gauges work?
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Monday, August 28th, 2023 AT 11:35 PM
Tiny
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Hi,

Chances are, there is nothing that could have been done to save the battery. Oftentimes, they do short internally causing a dead cell.

As far as the voltage gauge, it would be for the alternator. You really shouldn't need to install one because the system is designed to indicate an under or overcharging. Let me know your thoughts and if I can help.

Take care,

Joe
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Tuesday, August 29th, 2023 AT 5:40 PM
Tiny
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Are you saying the system will display an over- or under-charging indicator on the instrument panel?
On this Buick, the instrument panel shows no voltage indicator, only the standard collection of "idiot lights". The outline image of a battery displays and lights, if there is a problem, but with no information about over- or under-charging.
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Tuesday, August 29th, 2023 AT 7:12 PM
Tiny
JACOBANDNICKOLAS
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Hi,

if there is an overcharge, you should see the light turn on. At that point, the alternator output would need to be tested.

You could install a gauge if it would make you more comfortable. It shouldn't be too difficult to do.

Here is a typical design.

1) Identify the wires you'll need to connect the gauge. There are typically three connections: power, ground, and signal.

2) Power: Connect the positive terminal of the gauge to a 12V power source that's active when the ignition is turned on. This can be a fuse box or a suitable ignition-switched wire.

3) Ground: Connect the negative terminal of the gauge to a clean and solid chassis ground. Find an existing grounding point or create one using a screw.

4) Signal: The signal wire connects to a switched 12V source that's active when the engine is running. This is often the same wire that connects to your vehicle's voltage regulator or alternator.

The one thing that is important is that the connections are done properly and insulated. You don't want a short.

Let me know if that helps.

Take care,

joe
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Tuesday, August 29th, 2023 AT 8:07 PM
Tiny
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Thanks, Joe. Seems clear enough.
I'll let you know how it turns out.
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Tuesday, August 29th, 2023 AT 8:16 PM
Tiny
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You are very welcome. Take your time and make sure to shield/insulate the wires. Also, make sure they are clear of excessive heat and anything that can damage them.

Take care of yourself and let me know if I can help.

Joe
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Tuesday, August 29th, 2023 AT 8:20 PM
Tiny
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While weighing the best way to detect a failing battery or alternator in the future, I went ahead now with the ultimate solution-- to replace both battery and alternator, so both start at the same point. The car has a history of at least three owners, and I am the latest, inheriting all errors and omissions of maintenance.

Today, I finished the installation of battery and alternator, and so far, no problems. But what is your opinion about these VOM readings--

1. Battery voltage, engine off, VOM on battery terminals-- 12.65v
2. Battery voltage, engine ON, lights ON, VOM on battery terminals-- 14.70v
3. Battery voltage, engine ON, lights OFF, VOM on battery terminals-- 14.70v

I could have tested the alternator output, as well, but ran out of time.
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Saturday, September 2nd, 2023 AT 12:48 AM
Tiny
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Hi,

That indicates the alternator output. It is perfect. I have a feeling the problem won't return. By chance, did you check the voltages before the alternator was replaced? That would tell us if the battery or the alternator was the issue.

Let me know.

Joe
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Saturday, September 2nd, 2023 AT 8:09 PM
Tiny
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It was the battery.

And you will laugh that, when I ran the alternator check at my local O'Reilly's, the original Delco Remy unit returned values exactly in the middle of acceptable ranges.

Of course, I had installed the new alternator to permit me to drive to the store, unwilling to risk damage to the new battery from a possibly bad original alternator.

Reviewing the situation, I realized the new alternator is an O'Reilly's lifetime (yes, I was told everything rests on finding fault in the previous unit) alternator which promises to have a longer life than the previous, older unit.

And by not turning in the original alternator for a refund of a core charge, I could keep the older unit in readiness if the new alternator ever has a problem, and I need to take the new alternator for a service check. It is almost a commodities/future value question, considering the same alternator may no longer be available in a decade.

As if I had not had enough frustration today, the MiniFuse from fuse panel slot 2E caused a no-crank situation when I began the trip home. Remembering the same weird fuse behavior from only weeks before, I checked slot 2E, pulled out the fuse, and simply reinserted it. The car started immediately.

In all the time you have known me, I have had a no-crank security lock-out, followed 12 months later by a no-crank from a faulty ground to the fuel pump, followed 12 months later by another no-crank from a loose/dropping MiniFuse. This car has its share of electrical problems.
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Saturday, September 2nd, 2023 AT 11:34 PM
Tiny
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Hi,

LOL You have had your share of issues with it. But they all break. Not one is perfect.

Thanks for the update, and I'm glad to know you got it taken care of.

Feel free to come back anytime in the future. You are always welcome here.

Take good care of yourself,

Joe
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Sunday, September 3rd, 2023 AT 8:43 PM
Tiny
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Joe, two general questions. Having had the Buick 98 for about three years, I face some long-term maintenance concerns.
1. Should I change the ATF completely, since it never has been changed before? No performance issues, yet, and I read YouTube auto pundit Scotty Kilmer counsels against any ATF measure except adding fluid (if low)-- especially on older cars like mine.
2. Should I change / completely drain the brake fluid, since it never has been changed before? I want to avoid accumulation of water in the line, to prevent rust. So far, after a brief search, I have found no 2CarPros videos / tutorials on completely draining the brake system.
Both concerns are aggravated by the fact the previous owner's wife threw away all his service records on this car, so I start with zero background on its maintenance history and problems.
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Monday, September 11th, 2023 AT 2:28 AM
Tiny
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BTW-- The Buick 98 has 252,905 miles on its odometer.
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Monday, September 11th, 2023 AT 4:31 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,289 POSTS
Hi,

How dirty is the transmission fluid? If it is dark and has a burnt odor, leave it alone. On the other hand, if it still has a redish color and no smell, you will be fine changing it.

I'm still old school. I prefer removing the pan so I can also replace the filter and gasket. Many people have gone to a total flush for the transmission. However, that doesn't replace the filter or gasket.

As far as the brakes are concerned, it certainly won't hurt to flush the fluid. Here again, that has become a new selling idea over the past 20 years. My 1978 C10 has never been touched and it still works fine. LOL

If you want to flush the brakes, we don't have a link for it. However, I attached the manufacturer's directions below.

Let me know if this helps.

Joe

See pics below.
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Monday, September 11th, 2023 AT 8:37 PM
Tiny
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The OEM method described above is what I usually have done with other cars, but I was not sure it cleared all the old fluid from the system.

Apparently, it does.

Thanks, Joe.

BG
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Tuesday, September 12th, 2023 AT 12:50 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

It should get everything out. When you do it, make sure to start at the wheel farthest from the master cylinder and work your way to the closest.

Another thing you could do is use a brake fluid vacuum bleeder and draw the old fluid out one wheel at a time. You would be able to see when the fluid goes from dirty to clean. I attached a pic below of what I'm referring to.

Let me know how things turn out for you. I'm interested in knowing.

Take care,

Joe

See pic below.
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Tuesday, September 12th, 2023 AT 5:15 PM
Tiny
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Here is a question from watching videos from a variety of sources about changing the front brake rotors and pads. The mechanics involved in the videos gave different torque specs on securing the two front brake pad frame bolts.
One mechanic said to use 75 FtLbs, but the other said 50 FtLbs. How could that happen, when the OEM spec does not vary?
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Thursday, September 14th, 2023 AT 2:32 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Are you referring to the caliper to the caliper mount or the caliper mount to the steering knuckle?

Joe
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Thursday, September 14th, 2023 AT 6:21 PM
Tiny
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  • 170 POSTS
This video specifies a torque value of 75 FtLb:
https://www.1aauto.com/how-to-replace-front-brakes-1997-2005-buick-century/video/45543

The mechanic refers to the mount secured by the bolts as a "pad bracket" (at 3:08), and at 4:36, says he will torque its bolts to 75 FtLb.
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Friday, September 15th, 2023 AT 4:20 AM
Tiny
JACOBANDNICKOLAS
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Hi,

The caliper itself mounts on the caliper mount. That is the only torque specification I have. See below. As far as the caliper mount to the steering knuckle, 75 ft/lbs sounds right.

Let me know.

Joe

See pic below.
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Friday, September 15th, 2023 AT 7:48 PM

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