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2007 Chevrolet Impala

Question: alternator whine

Question

bmcmret, Baytown, TX, November 28, 2011, 07:50
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the alternator is whining, sometimes at startup sometimes after warmup. no warning lights and car works fine. afraid it may fail soon, getting more frequent, and louder. it doesn't sound like a bearing however i am not sure.
Thanks for any help.

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  • Answer #1

    patrick mannion from Greg Solow's Engine Room, November 28, 2011, 20:07
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     Master

    A bad diode in the alternator can cause a whining sound. I would listen to the alternator with a mechanic's stethoscope and look at the charge pattern on an oscilloscope before condemning the alternator. Also check the fan belt for alignment, wear or contamination.

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    bmcmret, December 01, 2011, 04:50
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    spot on and Thanks! replaced the alternator and problem fixed, Thanks again.

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