From recent info related to me by Ford mechanic working on my son's work van (good ole torque monster (7.3) that a Ford rep. looks like contamination is also was the reason for impeller breakage. Goes back goes to the casting process, and some block designs/casting processes used on the Duratec's and also the Zetec's ( mechanic said he had broken immpeller's on them also???) have had much more residual left. And later on after the heat cycles it will let go. I remember the first time I flushed mine a couple years after I purchased it new many pieces of casting residue and sand came out. I flushed that block and and heater core for several hours. I filled with water and drove til it got up to temp and back flushed. At 36k I replaced the pump just in case, it looked fine.
My 2 cents or more fuel on the fire?
Paul
98 Duratec built 07/97
