Tomorow i am going to test the fan to see if it stops right away when i shut the engine off. How should I test the idler pulley...or the alternator for that matter?

Would it be worth while just to replace the idler pulley as it is so cheap?

 

ok, like i said earlier, this sounds like an alternator or idler. if it is an alternator, you will hear it if you spin it on its own, it will sound slower but youll hear that the bearings arent as smooth as they should be. The idler shouldnt spin free. if you turn it by hand you should feel a bit of drag on it and it will stop when you let go, if it spins really free then its probobly bad, check for side to side play as well, there should be none.
Now that i think of it, my water pump kind of sounded like that before it started squeeling. I suggest removing the belt and checking everything for loosness and bearing play. if you turn something slowley and feel ANY slight binding or anything other than complete smoothness, that will contrubut significantly to your noise. sorry if this is a little hard to read, its kind of late here.

 

sounds like the power steering pump is going out.. check the fluid level in it.. sounds like it is sucking air!

 

my idler went out the day before thanksgiving.. it's a $28 part.. easy fix! but check your power steering pump it sounds like there's no oil in it

 

if there wasnt any oil in the PS pump, he wouldnt have asssisted steering.

 

I had a similar noise and I removed the fan and clutch from the water pump and the noise went away.

 

ok, so here is the update:

Topped up power steering pump, no difference

I cheacked all of the pulleys and sure enough the tensioner pulley had a little side to side play and wasn't totally smooth - i replaced it today, no difference.

The alternator does not seem to be making any sound but i am not 100% sure on that one.

The "Idler Pulley" if i understand right that is the smooth one in the center of the engine. It did not have any play and spun well but still had drag to it.

What are the next things to try?

As a side note after leaving it for a day when i started the truck (after changeing the tensioner pulley) it did not make the sound right away but over about 1 minuted it started and slowly got lounder till it was at the same sound as before.

 

Did you just recently change the serpentine belt? My buddy recommends no more than 3 cracks per square inch before replacing.

Since the belt works with friction, sometimes old belts tend to "slip" and polish the pulleys and/or your new belt.

I've been told you can scrub the pulleys down with a scotch bright pad to "rough" them up but don't know if this is appropriate in your case.

If you think its a bearing in the tensioner or idler pulleys you can put chalk on the edge so everytime it rotates you can see it come around flash. If that noise is right in sync on one of the pulleys, you could have a bad bearing in that pulley.

I haven't dealt what with your noise though so I'm not sure what the problem is!

 

i changed the belt last summer and i just checked, no cracks in it.