I changed the water pump on my truck today just to hopefully keep from having problems. It was the OEM pump, there was no play in the bearing and it turned smoothly however the weep hole passage had lots of what looked to be dried up grease/lube, not the normal very slight coolant leakage that lubes seal. Possibly if the grease that is in the sealed bearing is coming out of the bearing and exiting through the weep hole passage this is what is causing the bearing to seize and lock up. My truck has only 23,000 miles on it, but it appears that it was on the way to failure.
Now let me qualify this observation. I have been an automotive technician and have owned my own shop since 1975. So I have seen probably 1000's of failed water pumps in my lifetime.
Now let me qualify this observation. I have been an automotive technician and have owned my own shop since 1975. So I have seen probably 1000's of failed water pumps in my lifetime.