Most common cause is an idler pulley for the serpentine belt. One method for finding the offending pulley is to listen with a stethoscope touching the bolt that the pulley spins on. You can also remove the belt and feel for looseness or roughness in one of the pulleys although that won't always identify it. Generators and water pumps can make that noise too. Power steering pumps rarely make noise from the bearings, but they can make a lower-pitched buzzing noise if the fluid is low or there is air in the system.
Saturday, June 4th, 2011 AT 11:24 PM