Originally Posted By: Mackelroy
What do you mean when you say you've heard electrical noise in car speakers? Dont know what that means.
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I just meant I've seen alternators cause electrical wine in circuitry. and the wine or HUM can grow or decrease with RPM(as in follow it). Sounds like your hearing excessive mechanical wine from the alternator in just lifting the hood and the rebuilt one is making the same noise.
You know what, youre right. A mech friend of mine (who is in another city but hes very good with cars) told me to start the car, and I will see two plugs to my altnerator, a black one and a green one. Can see here,
http://oi60.tinypic.com/2q9cboi.jpg (sorry for sideways pic, you have to turn your head to the left to see it right).
He said to start the car, get it hot and unplug the green one. Check for whine.
I did this and guess what! started the car, let it warm up cause its -15 here today. Didnt want to rev the engine cold.
Unpluged the green plug, reved the car with rear defrost on, no whine. Even tried it a few times to confirm. Plugged the green plug back in, did same thing...whine is back.
Not sure how the car can still run with the alt unplugged but i was surprised. Im guessing the extra strain gets redirected to the engine.
So does that mean my first mech was right and it is the alternator? If so, ill go back Monday and demo for the guy and get him to put another one in.
I never would have thought that the odds of getting another alternator to have bad diodes as well. But like i said it happens and was a possibility.