x-type with 110k, started making noise from engine bay, sounded like water pump bearing starting to go, gotten progressively louder and now it is loud enough that I decided, ok 100k, replace the water pump... but I just read the water pump is actually on the drivers side of the engine bay not the passenger's side! now I'm stuck... what else could it be? tensioner? help...

 

For stuff like that, I usually unscrew the probe off of a mechanic's stethoscope and use the "funnel" end to isolate the noise. Using a BIG screw driver and touching the blade to places and putting the end of the handle to your ear can work, too.