My Ram a 2001 start making a high pitched noise like a whiney chrippin fan belt. MY truck having 70,000 miles on it I figured about time for a new belt. Replaced the belt still getting the noise. So I replaced the belt tensioner figuring it was wore down. Nope still makes the noise. I ran the truck with no belt and it made the noise. It only makes the noise when its warmed up if you run the truck cold it does not make it till then. Also if you speed up pushing the rpms over 2000 it goes away too. My truck runs great and has not problems other then the noise. Everyone I know is totally lost on this. I don't wanna take it in to the shop for an easy repair and pay out my *** if I don't have too. I also recently added a K &N filter intake and a new daul exhaust if that my have anything to do with it which I doubt. But who knows.

 

If you ran it without the belt, than that eliminates any accessory on the belt system other than the crank. Hardly unlikely that something in the crank seal would do this.
My next thought is a vaccuum/air leak sucking through a small hose or leak. It could be affected by a temp. sensor and change when warmed up. If you installed the intake, go through and make sure you didn't leave a hose off, or knock something vaccuum related loose/cracked/broken.

 

Hey i checked all the hoses and stuff I could think of I did find one hose that goes from the back of the K&N Intake to the passenger side valve cover pinched off. I striaghtened that out I will let you know how it goes when I drive it later. Well I drove it and you were right that hose was the problem!

 

my belt is squeaking too it started today at firts is was a clicking then it got to a squeek as i drove it for a while but mine is now leaking somekind of liquid? anyone know what it is