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Alternator overcharging problem...

Brett_jjj

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Was driving along yesterday and the alternator light came on and the tacho and speedo all stopped working, I also got an ABS dashlight come on. Drove the car home, still seemed to run ok. The dash etc would come back to life with the engine idling, but it would all go off again once the engine was revved, although the battery light stayed on constantly.
I checked the battery voltage on the dash, and it was showing 15 volts at idle, and went up to 19 volts with the engine revving.. I double checked the battery voltage with the tech 2 and it showed the same voltage readings. I let the car sit overnight, deadlocked, and I couldnt open it today, dead flat battery, so I opened the rear door with the key, (wagon), and climbed through to open the bonnet. I connected a battery charger to the battery and I replaced the alternator with a spare VS one I had lying around. After 2 hours on the battery charger, the battery was charged enough to get the doors unlocked and the car started..
It now seems like everythings ok again. I though it might have fried the battery, which is only a few months old, but its charged up again now and is starting the car no problem. I also thought that VS to VY ecotec alternators were the same, but no, the VS and VY alternators are slightly different and the lower mount is slightly wider on the VY units, but a VS unit still bolts up to a VY in an emergency. Ive now bought a brand new alternator from ebay for $150 with 3 years warranty, its 110 amp rated , Im not too sure what the original ones are rated at.
 

aussie4life11

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Sounds like a dodgie reg on your old alternator. just a thought.
 

oska

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all you had to do was replace the regulator it's about $30~40

standard on any ecotec commodore that's done 200k+ just like heater tap failure

soon you'll complain about battery drain on start up or when doing short trips, replace the starter motor before it becomes a problem
 

Brett_jjj

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Yeah, I first thought about just swapping over the regulators, but after checking out the old alternator, I found the bearings are heaps rough and noisy when its spun, theres also a lot of sideways movement ( around 2- 3 mm ) in the shaft. Ever since Ive had the car the alternator has always been heaps noisy, so it obviously needed new bearings etc, so I just fitted the VS unit until the new alternator arrives in the post this week. I recharged the battery yesterday, first by charger, and then by driving the car around, and there was no flat battery this morning, so the battery is no longer being drained overnight by the faulty alternator, shes all back to normal now, so all good.
oska ,the starter motor cranks the engine over heaps fast etc, so I cant see why I would need to replace that anytime soon.
 
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