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Is my alternator about to fail?

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Old Apr 28, 2009 | 11:16 PM
  #1  
fastlane350's Avatar
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Car: 1987 iroc-z
Engine: 350 TPI.. stock :(
Is my alternator about to fail?

Im running a 87 iroc-z 350tpi, this is probably my 5th problem within the first year of owning it sadly... but i still love my car so i will continue to maintenance it.

About 4 days ago or so i noticed a whining noise coming from my engine bay, it changes pitch as the engine goes through rpms so im fairly certain its either the old ac compressor, power steering pump, or alternator, However i cant quite catch what it is by ear. I put some power steering fluid in the pump since it was low, sadly this didnt help. I just took the car for a drive and noticed the voltmeter was reading a little under 8 at idle, and while driving it is slightly under 13, the lights also dim while ideling. The check engine light will go on and off periodicall, but i cant keep it on long enough to check the code.

I am about to take a 4 hour drive to my parents house in a week and i am wondering if i should worry about this? It hasnt died yet but im not really in the mood for it to fail in the middle of this drive... im driving through indiana which is pretty much nothing but corn, so id be stranded for a little bit.

Is my alternator, or possibly something else about to fail?
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Old Apr 28, 2009 | 11:19 PM
  #2  
383roller's Avatar
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Joined: Jan 2008
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From: Greensboro, North Carolina
Car: '86 Iroc-z
Engine: 385 stroker, vortecs, demon 750
Transmission: G-Force T-5
Axle/Gears: 9-bolt, 3.27s
Re: Is my alternator about to fail?

are your signals blinking slower?
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Old Apr 28, 2009 | 11:29 PM
  #3  
fastlane350's Avatar
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Car: 1987 iroc-z
Engine: 350 TPI.. stock :(
Re: Is my alternator about to fail?

come to think of it they do seem to blink a tick slower when the car is stopped at an intersection, i kind of want to say its always done that though, ill take a better look at that tommorow morning though, the car sortof wakes up half my apartment building
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Old Apr 28, 2009 | 11:55 PM
  #4  
383roller's Avatar
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From: Greensboro, North Carolina
Car: '86 Iroc-z
Engine: 385 stroker, vortecs, demon 750
Transmission: G-Force T-5
Axle/Gears: 9-bolt, 3.27s
Re: Is my alternator about to fail?

im no mechanic, but when your lights get dimmer and the signals tick slower those are good signs of the alternator going bad. if you are taking a long trip, and your alternator looks old i would have it tested at a auto parts store.
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Old Apr 29, 2009 | 09:01 AM
  #5  
kcallais's Avatar
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Joined: Mar 2005
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From: Tyndall AFB, FL
Car: 1985 Z28
Engine: 305 TPI
Transmission: 700R4
Axle/Gears: garbage 2.73
Re: Is my alternator about to fail?

Sounds typical of a failing alternator. Put a voltmeter (if you have one) on the charging line on the back of the alternator, and put the other lead on a good ground. Should be above 14vdc on a good alternator.
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Old Apr 29, 2009 | 11:35 AM
  #6  
1ADan's Avatar
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From: Pepperell, MA
Car: 1987 Trans Am
Engine: LQ9/L92
Transmission: 4L60E
Re: Is my alternator about to fail?

I also agreed that it sounds like a failing alternator. If this does turn out to be the problem, I highly recommend charging your battery before replacing the alternator; if the alt's trying to run the car and charge up the battery at the same time, you might be doing the job again in the near future.
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Old Apr 29, 2009 | 01:02 PM
  #7  
fastlane350's Avatar
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Car: 1987 iroc-z
Engine: 350 TPI.. stock :(
Re: Is my alternator about to fail?

The car seems to be running fine today, voltmeter in dash is reading 12 at most times, the gauge may just be old or something, but the noise is still going on, the AC in my car was not functioning when i bought it, and i am starting to think the the bearing in the compressor may be the culpret? I dont know anything about AC though, my first car didnt have it either. im going to have a friend of myn bring a voltmeter to check my alternator and battery though so hopefully it will tell me if somethings going on, ill check the tightness of the fitting in the back and clean the bettery terminals also while im doing this... But if that checks out legit then i suppose ill be fine..
Thanks for the help guys
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Old Apr 29, 2009 | 02:59 PM
  #8  
camaro_junkie's Avatar
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From: Vancouver, BC
Car: '86 Camaro SC, '16 QX60
Engine: 2.8 V6 POWER, 3.5L V6 N/A
Transmission: T-5, CVT
Re: Is my alternator about to fail?

Originally Posted by fastlane350
The check engine light will go on and off periodicall, but i cant keep it on long enough to check the code.
The code should be stored, so you can check it any time. Can't remember what all the codes are, but it could be something that looks totally unrelated to battery voltage though it actually might be.
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Old Apr 29, 2009 | 07:14 PM
  #9  
8t2 z-chev's Avatar
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From: belle fourche,s.d.
Car: '82 z28
Engine: L83 5.7
Transmission: 700r4-1985
Axle/Gears: 3.42 posi
Re: Is my alternator about to fail?

probably a shorted diode (quite common with CS 130s)
-just unplug the voltage regulator plug on the alternator
and start the engine-if noise is gone there is a shorted
diode in the alternator. If car was mine,i would swap
in a far more reliable cs 144 alternator-probably would
be almost a bolt in if bracket from '85-86 tpi with 17SI
alternator is used.
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Old May 2, 2009 | 10:52 PM
  #10  
wesrams1's Avatar
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Joined: Apr 2009
Posts: 86
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From: Austin Tx
Car: 1992 Camaro RS
Engine: 350 .060 over
Transmission: stock
Axle/Gears: stock for now
Re: Is my alternator about to fail?

Its definately your alternator. i had the same whinning noise for quite a while before my alternator completely failed. eventually your blinkers will slow down and when it completly dies your steering wheel will lock up and your pedals will feel stiif. I would take it out and get it tested at autozone. its really simple to install a new one and it will probly cost you aboutt 120 if you install it yourself
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