No, I wouldn't have a clue. You can listen by rolling a tube of paper (or use a paper towel roll and hold it near the various components. If it's the pump have it replaced. If it sounds like water gurgling, have it replaced. If it sounds like a grinding noise in the fans, have it replaced. If it sounds like any other noise, have it replaced.
If it is by any chance a loose wire scraping against the fan blades, tie the wire away.