I have a 2003 Nissan Xterra, 3.3L auto. I got a funny whine, its a low hum when idle, then turns into whine when you rev the motor. Pretty sure its the water pump, but would like to make sure.

From my understanding the water pump is ran from the same pulley/belt the fan is on. So if i pulled the belt off, and started it. If it still made the whine, then it would rule out the water pump correct?

and if that is correct then it could be any of the other pulley's or the timing tensioner. maybe?

any input would be greatly appreciated.

thanks