I went with a new pump from my local parts store (no core,a spare to rebuild, new pulley, etc.). Looks great but when I went to put the fan back on I discovered that the pulley shoulder under the fan was squared off instead of round like the original and interfered with the rivets on the fan. A little grinding took care of the problem but be careful. If I had used it like it was it could have led to fan blade failure.
