Alternator dying

GroovyCarrot · Post by **GroovyCarrot** » Sat Jan 01, 2005 11:57 pm

Hiho everyone. My alternator's dying, and before I either buy another off mk2keel or send it to the autoelectrician to have him look over it, I was wondering if any of you lot had any better suggestions. Basically, it has the following problems:

* When I first start the car, the batter warning light stays on until the engine runs at over 1,100 rpm. Once it's gone off it'll stay off, but it needs that initial blip to convince it that the alternator's actually doing anything
* Once the engine is running and the battery warning light has gone off, it'll actually continue giving a faint glow that flickers slightly with the engine, when the engine speed is below around 1000rpm, unless I turn an electrical component on such as the lights, when the warning light cuts out completely
* After driving to the top of the road, the alternator belt squeals slightly for a couple of seconds when I stop at the T-junction. It's very predictable, always squeals for exactly the same amount of time and in exactly the same place, very odd
* Driving at night with the lights on, particularly with full beams on so lots of power consumption, if I do a slow gearchange so the revs drop to idle and then come up again the alternator belt will squeal loudly, painfully and embarrassingly for a few seconds. The lights will also dim as it comes below 1,000 rpm. Doesn't happen if I keep it above 1,000-ish rpm, and doesn't happen if I don't have lights on.

I assume the problem is that something about the alternator is knackered, it's giving out less power than it should, at idle it's not giving out enough power to turn on the alternator relay that stops the battery draining when the engine's off so no power comes through, therefore if it drops below idle there will be a lot of drain on the battery which the alternator then has to reluctantly make up for when the revs come up again, so lots of strain is put on the alternator and the belt squeals with the added stress. Or something like that.

Anyone care to correct me or suggest a good way to fix it, or shall I just buy another second hand alternator? Annoyingly I have another alternator in the shed, which does pretty much exactly the same thing..

bstardchild · Post by **bstardchild** » Sun Jan 02, 2005 12:43 am

Tighten the belt slightly

Better still replace it and treat the alternator pulley to a bit of wet and dry to remove the chromed effect on the belt surfaces

Tahrey1043 · Post by **Tahrey1043** » Sun Jan 02, 2005 2:43 pm

yeah not worth arsing about for a belt that even the RAC dont think is worth over a fiver...

GroovyCarrot · Post by **GroovyCarrot** » Sun Jan 02, 2005 9:32 pm

Belt's as tight as it'll go, and it took a lot of heaving to get it there

(Oh for a belt tensioner more advanced than loosen the pivot bolt and pull like hell..) I've got a new belt waiting to go on just in case it's a lack of friction on the current one, oil contamination or whatever, but that doesn't explain the lack of oomph even when the belt isn't slipping. I've already had the end of the alternator apart and sanded the pulley slightly to give it some kind of a surface, but that didn't really help..

GroovyCarrot · Post by **GroovyCarrot** » Sun Jan 02, 2005 9:35 pm

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... eName=WDVW

Kaching!

Shiney...

Tahrey1043 · Post by **Tahrey1043** » Mon Jan 03, 2005 3:32 am

oh the temptation to snipe that and then charge you some ludicrous amount over PM...

i gotta go find something more interesting to do for the next 6 days to avoid that!

GroovyCarrot · Post by **GroovyCarrot** » Mon Jan 03, 2005 2:37 pm

Ooh, b***h

Thinking about it logically though, it's going to be the same alternator as a 1.3 golf, so there must be plenty floating around ebay, I'm sure.. but still, that one's new and shiney and I'd not be happy if you sniped it