I'd be looking at the tensioner, myself. Try watching the belt wear indicator to see if it's moving in time with the noise. If it is, I'd say it's about 80% certain that it's the tensioner making the noise.

 

i have a video finally, can anyone tell me how to put the video in a post?

 

I don't know how to but it might be easier to post the vid to youtube then post a link here.

 

ok so after struggling to figure out my old photobucket abd trying to upload it on here,i think i finally have a video. When i took the video it was windy and icy and cold outside, but the sound is noticable mostly around 0:04 and 0:15 0:21. sorry its a link, i wsnt quite sure about how to upload it into the post, and sry for the noisy wind from fan and the wind blowing i tried to pick up the sound in different spots.

http://s67.photobucket.com/albums/h2...trucknoise.mp4


does it sound like a bearing? a pulley? somethin with the a/c? what do you guys think?

...and i think im in need of some new break lines and a good washing.

 

Pick up a mechanics stethoscope or get a metal bar that is a couple feet long and press it to your ear and you'll be able to find the noise.

When you press a bar to your ear you want to push the piece of skin in front of the hole down over it with the bar and plug the other ear so it will block out everything but the noise coming through the bar.

It sounds like a bad bearing in a pulley to me.

 

My 97 Ram is doing the very exact same thing you are describing. I'm almost certain that it is the tensioner arm. Not the pulley but the entire arm that is making the noise. Look at your belt and see if it is moving side to side on the tenisor pulley. Mine does this and I think that movement from side to side is where the noise is made. If you notice it only moves every second and a half or so and more or less coincides with the high pitch sound. But I say all of this and I haven't had time to install a new one, but I'm 80% sure the tensioner arm is the problem. The entire arm is only like $60 at an auto parts store. I'm going to get to that one day!

 

ive been doin that with a pice of wood about 3 ft. it was loudest at/on the altenator, that i just replaced wich didnt help. yea it sounds like a bearing, but whats weird is it only does it or is noticable after the engine is warm. sounds like a fuel pump whine, but its not the fuel pump.

 

Mine only does it after it warms up. That is why I think it is the bearing in that tensioner arm. The tensioner arm is right beside the alternator. Try a piece of metal and listen. Sound will travel a lot easier through metal than wood. A long screw driver is what I've been using.

 

Easy with that stethoscope thing. It's nice that it makes finding a noise pretty easy, but man does it suck when you bang the thing off the side of something hard. ooo, that smarts.

 

so after investing this never ending sound, and isntalling a new altenator, a new idler pulley and tension pulley, the noise still presists, maybe even louder. now that i know its not what i replaced, im pretty sure that its the a/c. what should i start replacing on it? should i replace the bearing or the whole compressor itself? i dont know much about the a/c units, but it sounds like a bad bearing.