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 or decrease? It is very faint or non existent at idle. The ol girl has 160K.
I assume that you get this sound when you rev the engine in park?
It could be many things, but the bearing on the idler pulley is a good first suspect to look at.
I checked the Idler pully and it doesn’t seem to be coming from there but I could be wrong. I have more info. The noise starts at 2K rpm and sounds very much like a high pitched noise as if you had your window cracked going at high speed. It 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 dont think it is fan related. Help!