Noisey Alternator

[miksax]

Hey Guys-
Quick question: I turn my car on and I hear a knocking/rattling noise from the front of the engine bay. I am pretty sure it is coming from the alternator (its not a knocking from the actual engine), and I don't think it is any of the other accessories. The noise seems to start up after the car has been on for about 10-20 seconds. The car starts, runs, and performs as it always has. A person I called said it could be a broken ball bearing in the alternator. It is also the original alternator, if that helps. Any advice? Thanks.

Mike

 

[stangjunkie]

probably a bad bearing

 

[HISSIN50]

A mechanic's stethoscope can be helpful (be careful of moving parts while listening to noises).

A smog pump with vanes hitting the walls can make a nice racquet.

Good luck.

 

[PRO50SC]

A mechanic's stethoscope can be helpful (be careful of moving parts while listening to noises).

A smog pump with vanes hitting the walls can make a nice racquet.

Good luck.

Or remove the belt and start the car. If there is no noise, it's one of the accesories. Spin each one by hand and listen/feel for roughness.


Good luck!

 

[TheUser]

I bought one of those mechanics stethascopes a couple weeks ago. It might be helpful in certain situations I guess, but I couldn't really pinpoint where the vibrations where at specifically. Who knows, maybe it was just me or my situation.

Either way, they are cheap, so you might consider purchasing some. A friend said his dad used a screwdriver (plastic side to ear, metal side to component).

 

[HISSIN50]

James, it might have been something endemic with the noise you were lookin for. I have used one for years and for ticking and scraping noises (I have a bad smog pump, for instance) it really helps narrow it down (for me).

I might have a really sensitive stethoscope because every time I accidentally tap the probe into something, I almost pee my pants (it sounds like someone hit my brain with a cold chisel).

You very well might not like the scope, but I at least wanted to say that it might be useful for a different kind of noise in the future.

 

[Swarzkopf]

Well, miksax, any word on what it was?

I seem to be getting the same noise...when I first heard it, I about crapped myself as I thought I'd spun a bearing.

But now I'm 99% sure that it's coming from the alternator as well.

 

[Roland69]

My truck was doing the exact same thing and I put my hand on the alt and it was shaking like a bitch.