Just finished a DIY water cooler for my PM256.
I used a carbonizer unit and adapted the SS tank on it for the water storage tank. And used a auto AC evap for the radiator. I used quicke disconnects on the torch and coller so when I want to put it away I can disconnect each and reconnect the ends so nothing leaks. Also this was handy to attach a pressure gauge to set the pump pressure. I drilled out the end of the motor shaft and welded in a 1/4" shaft for the fan to attach for cooling both the water and motor.

Have fun
tom