Loud Watercooler Noise Issue

Yea, that's loud.

2 possibilities.

1. THe software or the BIOS thinks the system is running hot and need to run the fans on full, or you accidentally tripped a fan setting somewhere into Maximum cooling.

2. The fans are bust. I favor the first option though.... it sounds more like fast fans rather than broken fans.

Go through your settings including BIOS settings and see if cooling and fan speed are set to auto or silent or something else. Failing that, you could try new fans. These are good.
http://www.newegg.com/Product/Product.aspx?Item=N82E16835181040