Auto Parts: 92 honda alternator - original oem unit, honda alternator, added resistance

Question
hi - my question is about faulty alternator - i suspect wearing bearing due to age - and if unit that's wearing out can contribute to lower mpg, not just 1% or 2, 3, but 20-40% or so? i ask because last few months i noticed progressively worse and louder rattling and slight cluncking coming out of the unit, which was very subtle and hardly noticable only 1, 2-3 years ago but was definitely present, also few seconds of belt whine only at start-up which is suspect added resistance in alternator pulley due to bearing wear, at least that's my theory. so, that's around or about the time i noticed 3-6mpg drop in economy without any logical reason due to engine, fuel system or anything otherwise. so, what do you think, any chance there is a direct link to begining of faulty alternator unit that's still charging but has added resistance and decreasing and drop of fuel economy?? thanks for any info.

Answer
Hi rj,

If you are not totally correct, you're definitely along the correct path of thinking.

ANY additional resistance will result in lower fuel economy especially when the resistance is directly linked to the power-plant and occurs prior to the power being transmitted to the driveline.

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Thanks for the question, I hope this information was helpful to you.
Fred
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