Engine whine

2005 cadillac srx, v-6, auto.28,000 mi. Has had this whining noise, Sounds like power steering pump whine, but does not increase/decrease with steering wheel movement. Have taken to two (2) dealers that tell me this car is fine, noise is normal for this v6. Recieved a buletin from one of them explaining noise as timing chain related. Driving me nuts.
Any solutions out there?