I am obviously not Mike, but would like to contribute. I have been pooring over waterpump threads for the past 3/4 of a year and have come to the following opinion. It seems Ford changed to a white impeller somewhere in the 1998 build year. I think this must have been for a reason. I haven't seen anywhere where a waterpump has died with the impeller exploding and the impeller is white. BUT, the cars with the white impeller are newer and have less miles, so this may contribute to the whole thing as well.
With that said, I myself am not going to worry about this for two reasons. One, I know the 98.5's have white impellers and although there are many documented water pump problems, the majority are related to before the '98 model year.
Others will disagree; but heh, that is what this board is for.
