[bobbader]

The situation is that the aluminum fan is a casting and in order to have the strength needed for it to hold up, the inside dimension of the pulley around the nose of the water pump is slightly less than that of a comparable original pressed steel pulley. The other side of the equation is that water pump castings from different manufacturers can vary greatly in this area and, in actuality, can be very crude as far as finish in said area. The remedy, from the factory, would be to turn this part of the casting down in a lathe. But, since the water pump manufacturers are not the same folks as the aluminum fan manufacturers, the connection goes unnoticed. Add to that the fact that there are, and have been through the years, many manufacturers of water pumps with different casting molds. There is only one manufacturer of cast aluminum fans. Some water pump castings are smooth enough that the fit of the fan is not a problem. Others require grinding or filing. These cosmetic inconsistencies do not effect the mechanical quality of either the fan or the water pump. Each are manufactured and machined in the specific areas that require machining for proper function. The solution to the fitting problem is relatively simple if one has basic shop tools. This might be a bit of an inconvenience upfront but, it will lead to trouble free operation in the long run. The simplest answer, of course, is to READ DIRECTIONS FIRST. Unfortunately, in our hustle & bustle world we often move on without doing so. We all do it from time to time.

Enough said. I hope this answers some of the "Why don't they just ………….." questions.

Bob Bader