While I was installing the radiator and I had everything out, I decided to check the water pump and true to form, it too, was horrible. Even after three flushings with Prestone Super Flush, it still had deposits in it. I got a replacement high-flow water pump from Hesco. Not only does it move more coolant, it has better bearings for a longer life. The high-flow thermostat housing is also from Hesco, I just pulled it off of my other MJ. At this point I was at wit's end and if I need to go into this system again I'll probably blow the truck up or sell it. So, I decided to not mess around with coolant either and filled all the new parts with Be Coolant, which should also help extend the life of the system.