rebuilt alternator question

diana's 928 · 08-07-2010, 06:49 PM

I just recently installed a new alternator, after realizing the one I had was nearing the end of it's life while replacing my PS pressure hose, and the rebuilt alternator seems to be making a lot of noise. Its making a high, whining sound that gets louder after driving for a while and I'm smelling something burning; however only slightly. The burning smells faintly electrical and I can only see just a hint of smoke coming out of the engine...from where I cannot be certain.

I spoke to the company that I bought the rebuilt alternator from and he said to put a couple two or three hundred miles on it to see if the sound goes away. I am not too sure that it will. I will of course call him on Monday when he reopens but my question is, does this sound like a bad alternator? Can a rebuilt alternator suffer from this kind of symptoms?

I placed a stethoscope to the different engine parts and the sound in question does seem to be coming form the alternator but I'm not 100% positive.

Any thoughts or wisdom is very much appreciated.

Thanks again,
Diana

Maleficio · Maleficio's Garage

I bought a rebuilt alt from eagle electric something off eBay for $75. It works better than what I had, but the bearing is slightly noisey. Oh well, it's quieter than it was, and the belly pan caused most of the noise from rubbing the tensioner bolt, so I adjusted the shape of the pan, much quieter now.

laneyamps · laneyamps's Garage

Could be a tight bearing inside the alternator? Could be a bad rebuild? Heck, I went through 4 alternators before I got a good one! LOL

Mrmerlin · 08-07-2010, 08:57 PM

to test the alternator just remove the belt and see if the noise stops if your smelling something burning then i would not keep driving the car as other parts can also catch fire.
With the alt belt off spin the pulley see how it turns.
also inspect the radiator hose as it could be hitting the PS belt and the fan shroud may need to be adjusted.
If you have the wrong belt on the the adjuster may be at full length and the belt may not be tight and its slipping

bwmac · bwmac's Garage

When an Alternator charges it causes a high whine noise.
The harder it has to charge the louder the noise.
If it gets louder after driving and you are smelling something then either you have installed some wires incorrectly and it is shorting out and will catch fire, or, the alternator is defective. either way I would not run it until you have someone that can properly check it out.