[kathyricks]

The label directions on the pink antifreeze recommends flushing with the pink antifreeze itself, not with plain water. Yep that's going to get expensive, but all this trouble could have been avoided in the first place if you had simply refilled with the factory original (red) type coolant the first time you drained the radiator.

Running your engine for 20 minutes on plain water is not a factory authorized procedure. If your water pump seal could talk I believe it would probably say "don't do that because antifreeze contains lubricants that protect me from abrasive wear".