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'91 S-10 alternator


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01-20-02, 10:28 PM   #1  
greez_munky
'91 S-10 alternator

I own a '91 S-10. 2.5 (4 cyl.) w/ a serpentine belt. A little while ago I noticed that when I would come to an idle from higher RPMs, there would be a whining sound coming from my engine compartment. I checked it out, and came to the conclusion that it was my alternator, I was told to check the pulley for looseness, I checked it and it seemed ok, so I figured it was just squeaking for some reason or another, so I did the one thing I shouldn't have done, I put silicone lubricant on the part of the pulley that rides on the shaft coming out of the alternator. That really didn't help. It really started to get bad recently, so again I did the one thing I shouldn't have, I put more lubricant on the pulley. Then I started the engine up, when it was cranking it had a squeaking sound. It ran for a while, the whining sound would come and go, then my engine just died on me. I tried to crank it back up, but all that would happen was just that squeaking noise, and it was real slow, like I was trying to start it in sub-zero temperatures. We checked the battery and the voltage was low, so we charged it back up and tried to crank it again, it did the same thing and it dropped my battery voltage significantly. So my question is, if I had gotten lubricant on the belt, would it cause it to not turn any pulleys thus not causing the engine to turn. Or is this a problem with my alternator and does it need to be replaced? And if it does, how much do they usually cost? Thanks.

 
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01-21-02, 05:07 AM   #2  
Joe_F
Sounds like a wiped out alternator.

The whining is a bad alternator bearing. They are sealed and lubricating them from the outside is a waste of time. They are not serviceable bearings, they are replaced at rebuild time.

If you did an output test with a digital meter and didn't get:

12.5 volts at the battery, engine off.
14.2 volts running, no accessories on.
13.5 volts, running, full accessory load...

then you likely have a bad alternator. Replace it with an AC Delco rebuilt and be done with it. If the battery is old and weak (sounds like it), pitch that too for a Delco.

Check all your connections for cleanliness and being sound and you should have no problems. Replace your drive belt at this time as well with a good Dayco or Gates belt.

Done .

 
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01-21-02, 08:52 AM   #3  
greez_munky
The battery isn't that old, the date on the side says feb 01. After we charged it, the gauge on my instrument panel for my battery read just under 14, and when I tried to crank the engine it would just do that whining thing and drop it down to like 10 or 11. So do I really need to replace my battery (why can't I just put it a new alternator and charge up the battery to normal?), and also the drive belt is in excellent condition it looks farely new still, do I need to replace the belt? I know I am going to get a new alternator, but I don't know if I really NEED to get a battery and belt also. Thanks.

 
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01-21-02, 11:23 AM   #4  
Joe_F
Battery is probably ok, charge it.

If you think the belt is over four years old, pitch it. Time for a new one. A glazed belt will discharge the alternator. Not to mention you sprayed with oil and junk when you lubed the bearings .

I would pitch it. Cheap insurance.

Do not trust the dash gauge. Test the output with a digital voltmeter! The dash gauge means squat .

 
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