There were two types of plastic impellers, one white, the other black. The problem was with the earlier type of impeller, it would disintegrate over time, I'm not sure which was which, though. When I first heard of this problem I replaced my plastic impeller pump with an aftermarket part that had a metal impeller thinking that I avoided the problem, but the bearings went and It began to leak after 25K miles. I replaced it with a Motorcraft pump with the proper color plastic, meaning good quality, and I haven't had any problems. I think if you buy a Motorcraft pump it will probably be the improved type since the stock of earlier pumps are long gone. Do some searching in the archives and you will be able to find out which pump to look for.