What causes an alternator to whine (if not bearings) (engine, replace, lights)
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My alternator is making an electrical whine that gets louder with load. I've listened with a stethoscope and I'm sure it's not the bearings. It's not a bearing noise. It's a low, steady whine, not screechy or marble-y.The alternator tests bad under heavy load (with AC and lights and rear defrost, voltage drops below 13V and keeps dropping), but puts out voltage to spec when not loaded like that. I'm planning to replace it because of the bad test and the noise. I just would like to understand what's wrong with it for my knowledge, which is pretty minimal. Anyone know what could make an alternator whine besides the bearings?
Bad diodes. Just go ahead and replace it. It won't fix itself. Or if you want to, see if you can find a rebuild kit and give it a try if you want. I've rebuilt some of mine before. But they were older simpler designs. You will need at least a 100 watt soldering iron though. Those little cheap pencil type 30 watt jobs just don't do the job.
My alternator is making an electrical whine that gets louder with load. I've listened with a stethoscope and I'm sure it's not the bearings. It's not a bearing noise. It's a low, steady whine, not screechy or marble-y.The alternator tests bad under heavy load (with AC and lights and rear defrost, voltage drops below 13V and keeps dropping), but puts out voltage to spec when not loaded like that. I'm planning to replace it because of the bad test and the noise. I just would like to understand what's wrong with it for my knowledge, which is pretty minimal. Anyone know what could make an alternator whine besides the bearings?
98 Altima
Bearings, maybe. But if the radio is turned on and you hear an electrical whine that goes up and down with the engine RPM, then it could be that the radio needs to be grounded properly.
My alternator is making an electrical whine that gets louder with load. I've listened with a stethoscope and I'm sure it's not the bearings. It's not a bearing noise. It's a low, steady whine, not screechy or marble-y.The alternator tests bad under heavy load (with AC and lights and rear defrost, voltage drops below 13V and keeps dropping), but puts out voltage to spec when not loaded like that. I'm planning to replace it because of the bad test and the noise. I just would like to understand what's wrong with it for my knowledge, which is pretty minimal. Anyone know what could make an alternator whine besides the bearings?
98 Altima
An alternator is a three phase device. If a diode has failed or there is a bad winding in one of the phases there will be a gap in what should be a smooth production of current and the windings will whine. That this is the problem is confirmed by the poor output under full load.
Bearings, maybe. But if the radio is turned on and you hear an electrical whine that goes up and down with the engine RPM, then it could be that the radio needs to be grounded properly.
The theory about the radio does not explain the poor output from the alternator under load. There is a failure of a diode or a winding fault such that one of the three phases of the alternator is not working.
The theory about the radio does not explain the poor output from the alternator under load. There is a failure of a diode or a winding fault such that one of the three phases of the alternator is not working.
Don in Austin
Yes, that's true. I was referring a winning noise from the alternator. Bearings that are dry can cause that noise.
Could the fan belt be too tight causing too much load on the bearings?
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