[Aurel]

I had the same problem with my 78 SC. When I took the motor appart for a top end rebuild, I discovered that my fan housing was cracked in several spots. The deformation made to the housing was such that the fan blade touched it. My first guess was also alternator bearings, but they are fine. Those fan housings are made out of magnesium, and they do not age very well (just like the 2.7L mag cases). The fix is to replace the housing with a good used or new one.

Aurel