So far, I have 101,000 miles on my '99 Mystique water pump, with no problems. Two Ford service managers I've talked to swear they've never heard of any unusual problems with these water pumps. I've heard that sometime between '98 and '99, Ford switched to a nylon impeller, instead of the black plastic model. I've also wondered about excessive RPM's being the cause of the impeller failures. I rarely take my RPM's over 3500, although the redline is 7,000. I've wondered if aggressive driving is somewhat the cause of the premature failures. Routine high RPM driving might destroy the impellers quicker than "normal" driving.
