high-pitched whirr..alternator?

[kis86]

I'm hearing a high-pitched whirring sound when the engine is cold, and was thinking the alternator might be going bad.

It doesn't change depending on if the lights are on or off, but seems to get quieter if I turn off the heat all the way. If I rev it just a little, the sound goes "woop" and away until I let off the gas again. when it warms up it goes away and comes back, but not nearly as much as when it's cold.

like my sound effects? Not sure how else to describe it...

 

[SteelHeadz]

Does the Noise change when you turn the steering wheel? if so, check your powersteering fluid.

 

[kis86]

nope, no change on steering. I checked all fluids as well, steering is fine, transmission is fine, oil fine, coolant is fine too

 

[kis86]

also no change depending on being in gear, park, or neutral

 

[89 jeep yj]

Maybe the belt is in bad condition ?

 

[kis86]

I sprayed a little belt conditioner on, but no change. maybe an idler pulley would make that sound?

 

[Itchee96]

How about tightening the belt up?

 

[Collin the Hen]

If you can turn your alternator with your thumb, it's too loose, just in case you think it may be the belt.

 

[kis86]

I was able to pinpoint it today, since it got much louder. It seems to be coming from the idler pulley after all good deal, I'll just replace it...cheap part too!

 

[slo-wrench44]

you got lucky my original 88 alt went bad on my way home drove 33 miles with the heater , lights, and radio on befor i realized stuff messing up. had to replace it at -2 degrees in the middle of the night lol not bad for a jeep with 260000 miles on it.

 

[kis86]

Yuck!! yea, it could definitely be worse then...