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Model specific boards => Golf mk2 => Topic started by: silksnsc on 28 July 2003, 12:22
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I'd love to know if anybody has encountered this problem, I've got a 1988 8V with a Valeo 55 A alternator, cars fine until I put the headlights on, the lights actually seem to pulse and within 5 minutes the ignition lights on and within 15, the battery is flat and the car stops, I'm suspecting a very tired battery but anybody elses views would be gratefully received!
Cheers
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Well your battery is flat, but it sounds like your alternator isn't charging. Put a voltmeter across your battery with the car switched off. Compare that voltage with the reading you get with the car running. The voltage should be higher with the car running. It may be your diode pack/brushes which are cheap to replace.
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Rich,
Thanks for that, I'd be inclined to agree, but the cars doing 500+ miles a week in daylight with absolutely no problems, I could be wrong , but do you think the extra lighting load is just outstripping the batterys ability to hold onto its charge?
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I still think its well worth checking the alternator. The battery will last for ages at this time of year, as you say you don't need the lights, heater or rear windscreen demist etc. If the brushes are getting worn, you may still get a little out of the alternator, just not enough.
If the alterntor is working OK, you should comfortably be able to switch on the lights without it killing the engine.........even with a flat battery
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Rich,
I'm sure your right. I just would have preferred a battery swap against an Alternator stripdown, lol.
Thanks again
Bill
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The diode pack/brushes can be replaced simply by undoing 2 screws! You don't even need to remove the alternator from the engine. I'd go for them first, at least have a look at them and see what the brushes are like.
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just wondering if the warning light on the dash stays on when you run the engine. a sign of brushes wearing out is that the light stays on and when you rev your engine, it dims and maybe even goes out.
the easiest way to check for sure if its your alternator is to charge your battery overnight with a charger than next morning do a test.....
first measure your battery voltage, this should be somewhere in the region of 12 volts, sometimes a bit less so dont worry. a really good battery will read about 12.2 volts after a full recharge and left to settle for a while.
next switch on your ignition and start your engine. the voltage should have risen to somewhere in the region of 13.8 to 14.2 volts
if this is the case you need to then turn on all of your lights and sundries, demisters etc....this puts the alternator on a full load test. ... if the rugulator is ok, the voltage should drop to about 13.4volts or somewhere there abouts. it should hold this reading for a priod of time, say 10 mins. if the voltage remains around that mark then you can say to a major degree that the alternator is ok......
sometimes a bad connection can cause a load so check that all connections to the battery are clean and clear of any amalgum(the gases can escape from the battery, sulphuric acid causes corrosion). it is wise to use a grease/ petrolium jelly such as vaseline over your battery terminals to prevent this from happening
i hope this helps you to some degree.....