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battery or alternator problem?

Discussion in 'Truck & Equipment Repair' started by dirt digger, Nov 16, 2006.

  1. dirt digger

    dirt digger Senior Member
    Messages: 619

    my belts squeal when my headlights/auxillary lights are on. When the headlights are turned off the squealing stops. The batterys about 3 years old and the alternator is probably as old as the truck (9 years). So do i need a new battery or new alternator?...less lights is not an option..haha
  2. tsmith

    tsmith Senior Member
    Messages: 255

    Have you checked the tension of your alt. belt? Take a look at the belt also, might be time for a new one, those would be the first things I'd check. If those arn't it I'd be wondering if the alternator is making that noise. Also sometimes even a new belt will make alot of noise. What kind of vehicle is this on?
  3. tsmith

    tsmith Senior Member
    Messages: 255

    Another thought for you if the belt system is a serpintine type the tensioner could be shot.
  4. dirt digger

    dirt digger Senior Member
    Messages: 619

    the belts only about a year and a half old...i guess i'll add that it goes away once the RPM's get above 1200. It really ticks me off because when its damp outside or raining when my headlights and wipers are on it will squeal like no tomorrow when i start up from stop signs...usually right in front of a group of 15-20 people, they all look like my trucks about to blow up..haha
  5. tsmith

    tsmith Senior Member
    Messages: 255

    I looked at your profile, I assume it's the 97 f250. I looked at the belt system on the napa site, I would still go with the belt or tensioner. Check the tensioner first, I'm not sure of the lbs rating, but it should offer a good bit of resistance, If it is the belt you should be able to pour water on the belt while it's running and the lights are on, if after the water is poured on it goes away I'd say it's the belt, the squeal will return within a minute or so, some times belt dressing helps, but often you need a new belt even though it isn't that old. Let me know what you find.
  6. SnoFarmer

    SnoFarmer PlowSite Fanatic
    from N,E. MN
    Messages: 9,883

    You can try a belt first and see what happens.
    If it is a had alt you would want to replace the belt anyway.

    If it is a serpentine belt do not use belt dressing on them. It only makes things worse...If it's squealing replace it.

    But, I think it's your alt.
    Last edited: Nov 17, 2006
  7. I had the same problem with my 98 Dodge.I changed the belt ( which had some small cracks in it) thinking that was it and the squealing didn't stop, battery still ran low causing the low battery alarm go go on.My neighbor recommended the tensioner which I replaced and the squealing was gone. Then I had a problem with it cranking over. My battery was also 3 years old but I think I might have put excess wear and tear on the battery ( not to mention the nitwit at Sears sold me a smaller battery in 2003 by mistake and this nitwit didn't have the common sense to check out what he sold me) I just replaced it with a 1000cca Diehard and it cranks fine and I can turn on everything without a problem. Bring on the snow!
  8. jcesar

    jcesar Senior Member
    from Mi
    Messages: 492

    Got a Volt meter? If so, put the hot and ground on the battery terminals while running. It should be charging at about 14.05 or better. If it is lower than 14, change the alternator.
  9. dirt digger

    dirt digger Senior Member
    Messages: 619

    thanks guys, i'll give the voltmeter a shot. i was working on my truck most of saturday but that was dedicated to more important things....oil change, distributer cap replacement, welding on a new exhaust bracket...i've been so busy with work and school and trying to balance it all this alternator thing has been put on the back burner...but i got under there and tugged on the belt a little and it feels looser then the fan belt so maybe it just needs tensioning.
  10. justme-

    justme- 2000 Club Member
    Messages: 2,138

    The problem is the belt's tension. If it's a self tensioner the tensioner is going. Changing the belt is a temporary fix- as the new belt stretches (as this belt has over the year and a half...) it will squeel again.

    you answered it when you said it squeels in the rain. Tighten the belt FAST before you glaze it and need to replace it. (if it glazes you won;t be able to tension it enough without overtightening it and wearing out the bearins in the a/c and alt.

    Just went through this with the wife's car- belt is about 1.2 years old- it stretched.
  11. KuetherSnow

    KuetherSnow Junior Member
    Messages: 3

    aside from checking the tension you can try some olive oil on the belt always works for me
  12. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    You should not be able to move the belt or tensioner by hand at all. The tensioner's go bad all the time.Nine years old is ancient for one. They are about $75 or so at a parts store. Some years you can buy just the pulley and bearing setup.<---- Which, I would bet would do you no good.
    Your repair manual will show how to read the belt wear guide. I would also bet the newer belt is now fried, so replace the belt after a new tensioner's installed. Auto part stores will test your alternator for free. If they put the load to it and it makes the noise it's the problem.
    They sell the bearings and brushes for them too. That's a real advanced skill to get it apart and back together.
  13. Mick

    Mick PlowSite.com Veteran
    from Maine
    Messages: 5,546

    Kind of surprised at seeing someone recommend putting in new brushes. I thought that was a lost skill. I used to all the time, but the last time was about 15 years ago. Went to a NAPA store for brushes and the guy looked at me like I was looney and said "Nobody replaces brushes anymore, they buy the whole alternator". Then he told me to wait, he thought maybe they had a set for my car back somewhere. He did, but said they wouldn't be stocking anymore.

    $5 for a set of brushes vs $50 for an alternator. But I guess the labor charge for changing the brushes would make lot of difference if you weren't doing it yourself.
  14. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    I guess re-clocking* the alternator is another lost skill too.
    It's not real hard to replace the parts. Believe it or not AutoZone ( 5 years ago ) had the parts!
    But then I think of the windings and regulator being old and why not just spend some money and upgrade the amp rating while I am at it.
    I have a brand new starter with an ear broke off the mount. Next time my starter dies it's getting the mount installed from the old one.

    * Re-clock: Is to rotate the mounting flange on the housing to match the mounting points you have.