my 1982 Buick lesabre has electrical trouble

[Guest]

The car has a 307ci engine and it keeps on killing batteries. we have replace the altenator and battery both 3 times and it will work for a short time, but then we go out to start it and it is dead. Also sometimes the lights will dim while driving on the highway as though the altenator is not working. We think it could possibly be the voltage regulator. Any help on this would greatly be appreciated.

[56Roadmaster]

Hi,<BR> For starters the voltage regulator is inside the alternator and thus each time you replace it you also change the alternator. You should check the battery voltage when car is running with a volt meter 13.5-14.5 volts is normal. This is a quick check to see if the charging system is ok. Next with the car off and all lights of including underhood work light pull a battery terminal off and connect a test lamp between cable and battery if the light comes on (even very dim) you have a short or accessory that is not shutting down.you can one at a time pull fuses to see what circuit it is on(light out). It also could be a short in one the wires going to the starter often due to oil dripping on them from valve covers. Also check for wires lying on exhaust manifolds which may be shorting due to burning. One more thing if you get your alternators from those cheap parts stores they are often just cleaned up old units which may or may not have been tested, I know because I have run a couple junkyards and used to sell cores to the remanufacturers so it is possible to get 3 junks in a row. Now you know why they are such a good deal! Electrical faults are not always easy but you should go about it systematically.

[NTX5467]

Checking for a current draw with everything shut down is a good idea. On those particular vehicles, there should be nothing operating after everything is turned off--except, the time delay on the dome lamp, the memory and clock in the factory radio, and/or an alarm system that migh have been added. Also, in a car that age there could be some of the wiring (front light harness, for example) that could have come out of the factory convoluted protective tubing that could have chaffed and worn through against the core support (or other metallic body part), causing the high load or direct short situation which could dim the lights too (which should be blowing fuses too).<P>I have a '80s car that had a battery that ran down if it wasn't used for 2 weeks at a time, but if I drove it, it was fine. I got the existing battery warrantied, but that turned out not to be the problem, so I just unhooked it when I parked it in the building. One night, when there were no other sounds, I hooked up the battery, saw a weak spark between the battery terminal and cable, and heard a faint "chinggggg" from the chime module. I removed the cable and waited a while, then tried it again with the same results. I unplugged the warning/alarm chime module and ended the battery drain problem.<P>If the lights are noticeably dim while driving on the highway, it's either a very weak alternator or a pretty strong "short to ground" situation. Also be advised that a bad battery can kill a good alternator.<P>Also, the auto supply people might have these liberal replacement warranties on their parts, but their test equipment to verify "defective" parts they sell can similarly have liberal specifications of what is good or bad. There have been several times where the auto supply (chain store in this case) tested an alternator as "good" but it would not pass an on-the-vehicle load test by any stretch of the imagination (i.e., only putting out 10amps with enough load to drop the volts to 9 volts from the normal 14 volts, when it should be putting out more like 95% of rated output at that same load for a good one). Same with their battery checks too. These are things we've observed at the dealership level.<P>The other key thing is to make sure that whatever batteries you are getting are at least OEM specification in size and capacity. A too small battery will make the alternator work too hard to keep up and also generate too much heat in the process.<P>This brings up the last issue. Make sure the cooling area on the alternator is not obstructed by ANYTHING and has the factory specified cooling duct on the back (if needed). On the earlier alternators, the regulator and such are right behind the cooling holes so if there is not sufficient cooling air, these parts will overheat and cease to function--even on a quality AC-Delco item. Also, consider that on those earlier alternators, they cool from back to front (which makes having an unobstructed air source back there necessary).<P>I learned that last point the hard way. In the process of changing a water pump and such, the heater hoses came to reside right behind the alternator. The alternator went away after that. The AC-Delco alternator I put on (from our dealership stock) failed in a few weeks. I also added a new battery when the alternator went away (and I put on another one from our stock) and had the same thing a few weeks later.<P>When I put the hoses back where they should have been, the problem went away. Some engines in some applications also need the plastic cooling duct for the back of the alternator. It directs cooler air to the alternator in cramped situations--and is necessary. A customer had a Z34 Lumina (with the 3.4L DOHC V-6) that would need a new alternator every year (or about 15000 miles). Somewhere, the cooling duct had come off or not have been put back on during a repair or something. It wasn't too big of a deal as along as it was in extended warranty (other than the hassle and deductable) but that deal was ready to end when I took her call on day--and determined her vehicle needed a cooling duct that was not there. <P>Although the batteries and alternators could have been quality items, the other items on the vehicle which interact with them could also be causing their failure. Sometimes it's the little things that can cause larger problems.<P>Hope this helps,<BR>NTX5467