High pitched noise from engine

My Expedition started to make a Whurrr sound similar to having a window cracked while going down the road. It increases in noise as the rpm’s increase and starts getting noticeable at around 2000 rpm?s. It makes this noise while in park so I don?t think it is transmission related. The car is a 2001, 4.6 litre and has 160K. I replaced the Idler pully and that didn?t do the trick. The noise appears to be coming from the right front of the firewall area. I also checked the fan clutch and it moved but does not spin freely. When I push it, it rotates about 1/2 turn. I also turned off the fan so I don?t think it is fan related. Help!