My brain is almost fried trying to find out what is causing a noise in my 4 banger.

I have ownned my Avenger for over a year. A couple of weeks ago I noticed a rubbing sound coming from the front of the motor around the belts. Agaiin, the noise doesn't start immediately, but after you let the engine warm up it sounds like a belt rubbing against plastic. The serpentine belt is in great shape, yet the alternator belt was trying to run off. Replaced the aternator belt, still had the noise. Took the car to a mechanic, he said it was my idler pulley bearing. Replaced that, still had the noise. I ran the motor without the serpentine and still had the noise.

Now, after spending a few nights taking the dampener, motor mount and power sterring pump off, I looked behind the timing belt cover to see if anything was loose or if something was in the way causing the belt to rub. The smooth side of the timing belt has some indication of rubbing but nothing serious.

Has anyone ever experienced this problem??

Could it be the alternator? Usually if an alternator is going bad it will make a sound no matter when you the engine is running. The noise I have only surfaces after you let the engine warm up a bit.

Could it be the idler pulleys for the timing belt?

All help is greatly appreciated!!!

it might be the Timing belt tensioner going bad and allowing the belt to kind of flap around inside the timing cover...  Are you due to have the belt done and if not and you had it done before did you replace everything in there??  I can speak from personal experience, if you do not replace EVERYTHING (ie. tensioner, idler pulleys, belt) they have the potential to fail and cause massive problems.

I work for NAPA and I had to get it from the dealer.  That and HOW DARE YOU!!!  Autozone or Advanced, for shame, FOR SHAME!! 

where are you testing the tension on the belt, if it is between the cam pulleys it will be tight there, but it may be flopping around down where the tensioner and the idler pulleys are.