Here’s the quickest and easiest way to replace the water pump on a 5.9 Cummins. This is a 2006 Dodge Ram 2500. At the front of the engine is the serpentine belt. The water pump is driven off this belt. It’s number 9 on this diagram, on the left upper of the engine. To pull ot, you first have to loosen the belt. That’s done by putting a bare half-inch ratchet onto the belt tensioner, best accessed from below the truck. Pull down, loosening the tension, and simply slip the belt off of the alternator. Easiest if you have one guy below, one guy above. Then drain the coolant, so you don’t make a huge mess pulling the water pump. There’s a drain petcock on the bottom driver’s side of the radiator. Loosen it by hand and the coolant comes out in an orderly fashion. Pop the radiator cap to make it flow faster. While that drains, remove the air filter box. One ten millimeter bolt, plus a flathead to loosen the intake clamp, and then pull the sensor. This gives you access to the water pump from the passenger side. Reach in there with a ratchet with a ten millimeter socket, and loosen the two bolts holding the water pump on. Clean the gasket surface by scraping it with a razor blade and spraying some brakleen. Install the new gasket on the new pump, and install it, weep hole down. Tighten the bolts evenly to about 18 foot pounds. Then install everything in reverse—belt, making sure it’s routed properly and seated on every pulley correctly, then air box, not forgetting the sensor, then close the drain petcock and fill with new G05 coolant, mixed 50/50 with distilled water. Run the engine up to temp, with the heater on full blast, so that the thermostat opens and coolant fills every part of the system with no air bubbles. When the upper radiator hose is turgid with coolant and hot to the touch, and no more air bubbles escape the top of the radiator, you’re good to go. Replace your water pump if it’s making noise or leaking. It’s a common repair on any vehicle, often lumped in with other services.