2 New Gates Water Pumps Bad???

On Father's Day (2020), I bought my 1968 Plymouth Satellite. The owner had recently (2 months previously) replaced the water pump because he said he was getting too much coolant from the weep hole. He bought a NAPA (Gates brand 40030?) and installed it. I bought it and after 130 miles, there was a BANG and the impeller came loose. The belts came off as the water pump pulley wobbled loose. My first repair on my 'new' car was to replace it. NAPA warrantied the pump and I then put on a new (not rebuilt) water pump. I used RTV on the pump (not block) and the gasket. Also RTV on the threads of the long bolts. Torqued in a cross pattern and reinstalled everything else (alternator/steering pump). Everything has been good, but last night I took my wife for ice cream and parked the car in the shop afterwards. This morning there was about 3/4 gallon of coolant on the floor (i confirmed by checking the radiator level). I checked the tightness on the water pump mounting bolts and none were loose. It looks like the weep hole is dripping (not happened for me yet on this new pump). I understand that a few drop is normal, but this is WAY more. I'm guessing the second new pump seal is bad and I'm planning on contacting NAPA about it. Just wanted to see if anyone had any other insight before I start complaining. Also, if Gates is crap, what brand pump should I be using? I'm not looking to do an electric pump at this point. FYI: the engine is the original 318 that has been stroked to an approx 390 with edelbrock aluminum heads, weiland aluminum intake and was professionally done in CO in 2016 (i have the receipts). Estimated hp was 400-450 in case that helps. No i didn't go crazy on the way to get the ice cream, just a nice cruise. Thanks for any help!

I think that when you purchase parts at NAPA, you are going to pay more, with that said, I think for the most part, their quality is usually the best. I don't know about Gates quality ??? I think I would try a different brand, could be a manufacturing problem probably come from over seas as most parts do now. Perhaps a MOPAR parts supplier would be the way to go. More expensive YES, but you probably won't be replacing it again all too soon. Fingers crossed.

GMB pumps have served me well. I really haven't seen any real issues here, and I use or get for customers a good quality water pump instead of the cheap chinesium ones. Are the belts too tight? I haven't seen a rebuilt water pump in decades; do they still sell them? Doesn't matter to me, I always buy a new pump.

On the face it sounds like Gates had a bad lot of WPs. It happens to pretty much every company that is a manufacturer of some item. Gates is a good company and make probably the best belts there are. I suspect however that they private label the water pumps and that someone else makes them, perhaps off shore. When you have this type of arrangement, problems can occur that may take some time for the manufacturer to fully comprehend and act on.

There are plenty of brands of pumps out there, Gates is typically going to be one of the better ones, but everything man made will have a problem at some time. If it were me, I would reach out to Gates directly and explain the situation to them, they might not do anything but if they are worth a crap they will be interested and may replace the pump.

The weep hole should never leak.
Just an FYI

A FlowKooler water pump is a great choice. It requires that you install a hi flow style thermostat.

I will second GMB.