what normally fails in the water pump?

[stackz]

145k 2001 3.0 vehicle.

I'm going to be doing my oil filter housing gasket in the near future and really thinking of doing the water pump at the same time as I dont know if its original or not.

is it the bearings that give out or the plastic impeller that falls apart?

should I just go with an oem replacement or one with a metal impeller?

I only know of a metal impeller unit from another thread I randomly came across on here months ago and its stuck around in my head but I have no idea who makes it or how much it costs...