Anyone give me some advice about my alternator / Serpentine drive belt?

Hello,
I have a question below about grandfather's 93 dodge caravan / plymouth voyager. Its a 3.3 and the serpentine / drive belt has 6 groves running the
length of it if that helps.
Is this the appropriate newsgroup to post a repair question or is there a better place?
I noticed last weekend the serpentine drive belt began squeeking but I didn't think much of it at the time as it hadn't caused a problem.
My grandfather went to start the car yesterday morning after driving home from work with the lights on the night before. When he got in yesterday morning. It wouldn't start due to a dead battery. I charged it for a few hours on a slow charge and then tried to start it, it would run for a few seconds but only when I kept my foot on the accelerator and when I took it off it would stall. So I gave it a full charge over night and it appears to run fine today, but I'm worried that it's not getting a charge by the car and I don't want him to get halfway home and have the battery run flat on him and have him on the side of the road.
I'm trying to add some tension to the belt as it began squeaking when ideling and accelerating the other day. At the same time I noticed that my headlights, digital clock, and dome lights are dimmer until I rev the engine, when they return to normal until I take my foot off the accelrator.
I'm assuming I either have a belt problem, a belt tensioner problem, or an alternator problem.
I took a look at a chilton manual last night and according to the diagram of the belt tensioner, I just needed to put a 15mm wrench on the nut and go counter clockwise to tighten the belt up. I moved it as much as I could (its hard to get my hand and a shortwrench in there so theres not much leverage) it tightend slightly (very slightly) and the squeek disappeared for about a half a minute before it came back. The belt appeared to loosen a bit as well.
Is there another way to tighented a drive belt or is it an indication that the belt, tenisioner and or alternator needs to be replaced?
I have a little radio shack multimeter if that will be of any help diagnosing the problem.
thanks for the advice, I'm over my head here...
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There's usually a second bolt the other side of the alternator that needs slightly slackening first before the adjuster bolt will work properly.
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Most serpentine belt systems have an idler pulley that self adjusts the tension.
--
*I don't have a license to kill, but I do have a learner's permit.

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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You might find an American group knows more about it than us Brits.
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Skipweasel
Never knowingly understood. (Ivor Cutler)
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If your manual said to turn the nut anti-clockwise, that may mean that you slacken the nut to allow a spring to tension the belt, then re-tighten it to keep the tension. (I'm not familiar with your vehicle) Either way, you first need to get the belt tensioned, then your multimeter will tell you the voltage with the engine running. Ideally you should have at least 13.8 volts with the engine ticking over and the headlights on. If this is not the case, you need a battery and alternator test to decide which is at fault.
But you won't be able to make any progress without belt tension, that has to come first.
HTH Steve
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hi steve et all,
where do I measure the voltage at? across the battery terminals? At the alternator? If the later, how?
As to your question, you have it right, manual says anti-clockwise will tension but the tensioner really seems to be just a pulley and the nut in question is in the middle of the pulley (as if it would just hold it onto the engine block) so I don't really understand how adjusting that nut alone tensions it.
Perhaps someone else can tell me if that sounds about right to them. I know older alternators use to have two bolts you could loosesn, slide the alternator and belt to the correct tension and then tighten up again, but I'm not particularrly familary with this type though the guy at my auto parts store says that almost all front wheel drive cars now use this method.
thanks for any advice you can give...

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It sounds like it has a separate wheel as a tensioner, ie. the belt runs round it. Some cars have this, mine does, but the nut in the middle of the wheel is not for tensioning. The tensioner wheel may be on a bracket that has a bolt at the bottom of a bracket that moves the tensioner wheel up and down, against the belt. Look for that.
-- Stuart
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wrote:

If the battery is more than 3-4 years old you most probably have a battery problem. Dying in cold weather is usually the first indication that it's on its way out.
--
Peter Parry.
http://www.wpp.ltd.uk/
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In General: most serpentine belts are tensioned automatically by a spring loaded tensioner, this is usually fitted with a 15 mm bolt head, this is used to SLACKEN the belt so that it can be replaced, there is no provision to tighten the belt beyond the available spring tension . If the belt is slack, replace it.
If you do have an adjustable set up, then there will be provision to slacken a locking bolt and wind up an adjuster.
to check charging set meter to a suitable dc scale (20 volts is a common area) connect across the battery, it should read about 12.7 volts, start the engine and rev it up enough to put the charging light out, the voltage should then read at least 13.5 volts, possibly as much as 14.5 much more shows a fault, no rise or drop shows a fault.
mrcheerful
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It's difficult to tell without seeing the diagram, but when you mention a bolt to turn with a 15mm wrench, does the bolt have a sort of toothed cog built onto it that engages with a sort of curved, slotted bracket? and, perhaps has a locking nut? (Owners of UK based VW Polos of the mid-90's will know what I mean)
If that is the case then you will find 2 bolts in line (or perhaps a very long one) about which the alternator can pivot, with the 3rd one - the adjuster bolt - sliding through the curved slot which will be like the circumference of a circle that the adjuster bolt makes as the alternator pivots. The alternator pivots away from the other pulleys to increase tension, and of course towards them to slacken off and remove the belt.
You have to slacken the pivot bolt(s), and turn the adjuster bolt to adjust the tension of the belt. With a bit of luck the adjuster bolt will have a locking nut that you can tighten, then tighten-up the pivot bolts. All a bit awkward till you get used to it.
I'm not sure if I've explained it very well, but hopefully you'll get the idea.
NB if the belt has been slipping, it may be as well to fit a new one, or perhaps slosh some chalk dust on it to get a bit of grip.

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That type has a much larger main nut, about 19mm iirc with a 12? as a centre locking bolt, also, I think that was on the v belt setup, not serpentine.
mrcheerful
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