As for the growling, it's more likely the bearing behind the fan than the fan clutch. About $140 as I remember since the bearing is part of a bigger assembly.
There are two seals in that area. One is the cam seal as mentionted, but it's not an o-ring. The other is the u-shaped seal between the upper timing chain cover and the lower timing chain cover. Sealant is used between the upper timing chain cover and the head.