Alternator noise

[Froggys86]

I'm trying to figure out why at times when cat is idling the alternator makes like a whirring squealing noise doesn't happen all the time.I've had it tested numerous times in the car and bench tested as well and was good all times....any suggestions or help is greatly appreciated...thank you.

 

[pontiacgp]

That could be caused by a weak battery causing the alternator to overwork, or poor battery connections

 

[Froggys86]

It's a brand new battery....not that new now,but only about a year old if that.

 

[pontiacgp]

It could just be the alternator then with the components making noise. I had one like that and it was working perfectly but the stupid thing would just whine all day long...and it wasn't the belt or bearing

 

[Froggys86]

Yeah it happens once in a while just irritating me..so maybe a new alternator or replace certain parts

 

[pontiacgp]

Yeah it happens once in a while just irritating me..so maybe a new alternator or replace certain parts

I would check the ground wires coming from the battery to the engine and body. Mine would whine nearly all the time....

 

[Froggys86]

Will do...usually when I'm at a stop and starts doing that usually brake and give it a little gas so it stops, embarassed by it.Thanks for the help post if it stops.

 

[pontiacgp]

That could be the belt is slipping a little in certain circumstances. If it's the serpentine belt I would tighten it a little

 

[Jeff L]

I have replaced 2 alternators with the same issue. I noticed the whine too and it was worse if I was using accessories like the lights, radio, etc. In my case the battery was either new or checked out as ok like yours. Putting in the new alternator and no more whine. Did not have any further charging system issues.

It is good advice from pontiacgp in checking your wires. Other cars I have looked over had buildup on their battery connections and bad cables which caused charging issues.

 

[Froggys86]

Come to think of it I think the pulley is a little wobbly when it's on that can be the cause and the to check belt for any wear and tear..