Everyone keeps saying that their aux fans are so loud on their W123's. Mine is quiet. I can barely hear it when it is working and it does come on all of the time because of the AC. BTW, I run only about 30% coolant and two bottles of Red Line Water Wetter. My tem usually only gets to about 95 and sticks their in the mid summer with the AC on full. Anyway, my fan has only been quiet. I don't know, maybe I just got lucky or something.