I will try to describe this noise the best that I can. It is a buzzing noise that is coming from the engine were the the fan is. If I put my hand on the fan housing I feel a vibration. I guess the best way to describe the noise is a noisy electric fuel pump that goes up and down with the rev of the engine. Thanks for any info.

 

Could be the bearings on the alternator is going. One way to test is to take the belts off and free sping the alternator with your hand and see if it spins freely or make any noise.

 

Could it be the belt tension sensor? Black wheel that runs outside the innermost belt, left side of belt.
chuck

 

It is louder when cold, If I remove the belts can tell the difference between the bad fan hub bearing or the alternator? I just replaced the belt tension sensor.

 

Yes you should be able to tell which one that's causing the problem, they spin independently of each other.

 

Thanks Robin.