Our Community is 940,000 Strong. Join Us.

'97 Lesabre - Bad Alternator?

10-13-2014, 08:29 AM
Hi guys! My '97 Lesabre is giving me some what of an issue of battery vs alternator. I retired last year and the car isn't getting the use it had when I was working. I replaced the battery last December and have had to force myself to just run the car for the sake of running it, otherwise the new battery would go dead (even in weeks period) and I would have to charge it. Last year we changed insurance companies and to get a reduced rate, they required plug-ins to monitor your driving habits. I suspected that being added and the factory security system being armed might be enough to discharge a new battery. I began by locking the car w/o arming security and all seemed to be working, along with driving the car more. We just returned home from a one week vacation, the buick resting in the driveway. When I went to start the car, I got the similar "I am dead" clicks and a very pronounced thump. I put the 10amp charger on for three hours and started the car. Engine runs rough, alternator gauge on dash is up and down at idle, can't get a clear screen on the OBD for codes. My question is, could this have been an alternator going bad all along, draining the battery when sitting idle/little use and now the roughness in the engine? I can easily replace the alternator, but don't want to be chasing dollars finding the fix! Any suggestions will be appreciated! :confused:

10-13-2014, 12:10 PM
Local Autozone can test your alternator. Do you have rear air ride suspension? If that's leaking then your pump will come on periodically to keep it afloat. It'll drain the battery if left long enough. You could try disconnecting the pump and see if the battery holds the charge. Doesn't answer the rough idle though.

10-13-2014, 06:25 PM
Thanks Kenny! I took the old rear air compressor out years ago. Nothing connected to that old wiring. But, good suggestion, if I still had it!

Until now, this car has never run rough! I think when I tried to start it on a dead battery, something must have cooked inside the alternator. The AMP gauge goes from a little over half at fast idle to discharge at "foot off" idle! Another thing that is strange, my A/C is only blowing out at the windshield. Also, my OBD which has never failed me will not illuminate to check for any codes for the check engine light. Really has me baffled!

10-13-2014, 08:18 PM
If you have a capable meter, you can hook it up to check for draws. By using the min/max setting on it you will be able to see if there are any spikes.

10-13-2014, 09:07 PM
No, I don't have a meter. Not knowing if it was the battery that took the alternator out (if that is the case) or the alternator that took the battery out, should I chance installing a new alternator and assume the 10 month old battery is still good? I don't want to harm the new alternator! :confused:

10-13-2014, 10:34 PM
Like Kenny said, most auto parts stores will test battery and alternator for free...

10-13-2014, 11:28 PM
You are worried about money? Apparently , you seldom drive the car, so why don't you cancel the insurance until you want to use the car. Then go to the computer and change the car and then change it back when you garage it again. Geico never gave me any trouble for doing that and sometimes gave me a refund if it was a preferred car.

10-14-2014, 06:27 AM
Money isn't the issue here. I only provided the insurance information (monitoring device) as an item that has been added to the car's energy demand. The car is not a daily driver anymore, but is used when needed.
Problem is, I am using it when I don't need it just to keep the battery charged. Now that something has happened with the electrical system, running rough, erratic voltage readings etc. this is the problem I am trying to solve.

I see where many say Auto Zone can bench test an alternator but have also seen negative comments on their alternators? Anyone know if Advance Auto does bench testing of alternators? I'll try to call them this morning.

10-14-2014, 08:22 AM
I think most have a "checking" station for off vehicle checks. They can even check the charging aspect of the alternator, though it sounds like that's working ok, while it's still on the car. Not sure about shorts or other faults. A meter that can be hooked up to show amp draw, as mentioned above, would let you know if there's excessive draw. The only other thing I can think of is a bad ground/loose cable. Every time you lose ground the car goes through a higher draw on the battery than when it reboots vs just sitting. I've seen this cause wacky things at start up as well. Good luck.

10-14-2014, 09:54 AM
Thanks Kenny. Taking the alternator out and I'm going to have Advance Auto bench test it. We shall see. I am also having the Interstate 10 month old battery load tested before restarting the car! I've had plenty of these replaced in the past!

Tech II
10-15-2014, 09:28 AM
I don't like bench testing....more often than not, an alternator fails when hot.....in lieu of doing a draw test, if you are not planning to drive the car for a few days, just disconnect the battery.....then when you do use it, reconnect it.....if you have no problems starting the vehicle, then you have a possible draw......if you have a problem, then you have a possible bad battery(can't retain a charge).....

You can test an alternator yourself with a simple voltmeter......the test should be done with the engine cold, and also at normal operating temp, under a load....

10-18-2014, 03:19 PM
Tech - I took the battery back to Firestone. The battery was bad and they replaced it under warranty (10 months old). I pulled the alternator this morning, took it to Advance Auto and had them bench test it and it showed good! The rep there said the test can show good as far as the integrity of the windings etc. but may not pinpoint an intermittent problem such as the internal voltage regulator. Like you said alternators might be more prone for failure when hot or under load or intermittent problem? I went ahead and bought a new alternator, seeing it was already out of the car and not wanting to take a chance on the old alternator (17 years old) with the new battery. Is there anything else besides these two components that could have started all this? This all started as just another dead battery! I hope I am good with having both new battery and alternator! :rolleyes:

I hope to give a "thumbs up" tomorrow that all is good! They had to get the alternator out of their warehouse for delivery tomorrow morning! Thanks again for all the feedback you guys are sharing with me!

Tech II
10-18-2014, 11:24 PM
The other possibility is a "draw".....

10-19-2014, 09:30 PM
Okay, I promised a hopeful update. Alternator and battery installed, held my breath when starting! Car started, dashboard voltage gauge hesitated for a moment and then responded like a new alternator and battery should! Engine was a little rough for a few and then settled down. I took the car out and drove it some 15 miles or so and by the time I returned to the house, the Buick was running as smooth as ever! I have "high hopes" in what I have done. Hopefully there will be no more setbacks! Can't say for sure what exactly solved the problem. Firestone said the Interstate battery was bad which they replaced. Advance Auto said the alternator checked out "good" but could not rule out possible intermittent internal component failures. I am smiling a whole lot more this evening than I have this past week. Thanks so much for all your feedbacks! With all the new technologies, you think you might be going in the right direction, but it's nice when you can ask for help from others who are more knowledgeable! Thanks again!

10-19-2014, 11:04 PM
Congrads. Invest in a meter. Plenty around for under $20.

Add your comment to this topic!