Unless you have one that malfuntioning. My old one was so damn loud on the hwy when the a/c compressor kicked on. It was loud till you got over 65 and then you didnt hear it anymore. I've never heard of anything like that but it did it. I still dont understand why the a/c compressor engaging had anything to do with it. I had a long thread about it a while back and no one could really explain it.
It was a Carquest POS, way overpriced fan clutch. Avoid them, they suck. I got an OEM one and it works a lot better and is silent on the hwy like it should be. I only hear it roar on when i first start it up and when it hot and I'm in traffic.