Here's a weird one.
I recently replaced a bud's '99 water pump in an effort to get rid of a horrendous drive belt noise.
As it turned out, both the belt tensioner and idler were at fault, but, and this is where it gets strange, the pump impeller was starting to wear the pump housing away ! There was actually a wear pattern on the housing from the impeller....
Mind you the pump seal was not leaking, nor the bearing making any unusual noises
I've replaced many a Ford water pumps before, but this one is strange...
BTW, the pump was the original unit with 130k on it
Has anyone else seen this happen?