A leaking water pump can quickly damage the otherwise very reliable Jeep Cherokee Engine. The water pump can be changed by a home mechanic with some patience and ordinary hand tools.
When the Jeep Cherokee water pump seal fails, it will leak from the weep hole in the bottom of the pump. Since this hole is behind the pulley, it is often hard to see where the fluid is coming from. Often a water pump leak will be misdiagnosed as a leaking hose as the fluid runs down and drips off the bottom of the hose.
Begin by letting the Jeep cool. Remove the radiator cap and make sure there is no pressure in the system.
Remove the electric fan. It unbolts from the header at the top and the bottom sits in two tabs at the bottom of the radiator.
Place a pan under the Jeep to catch the anti freeze and remove the lower radiator hose. Let the system drain. Next, remove the heater hose from the tube attached to the water pump. Be careful with the tube as you will have to reuse it.
Break loose the four bolts that hold the pulley to the water pump but do not remove them. If the tension on the belt does not hold the pulley from turning, use a square section screwdriver between two bolts to hold it while breaking loose each bolt.
Remove the tension of the belt at the power steering pump. On the earlier versions, the whole power steering pump moves. On later ones, there is a separate adjuster pulley. Move the belt out of the way.
Finish removing the bolts and remove the pulley. Now you can access the four pump mounting bolts. These have half inch heads, not 13mm and one bolt is longer than the others.
Remove the two bolts that hold the power steering pump bracket. These are 15mm on some and 9/16 on others.
Now pry the pump away from the block. If this is an original water pump, there will be a pry tab on the top of the pump by the metal pipe. Many aftermarket pumps do not have this pry tab.
Twist the pump out from under the power steering pump bracket and carefully remove it from the Jeep. Place the pump in a vise and remove the metal pipe noting its orientation.
Put some thread sealer on the threads and install the pipe in the new water pump. Turn it until it is aligned the same as the old one was. It should stick straight back from the impeller.
Use some sticky gasket sealer like permatex to hold the gasket on the water pump. Clean the front surface of the block down to bare metal. This is probably the most time consuming part of the whole job. Use a scraper and some chemical gasket remover if needed. The block is cast iron, so you can be aggressive when scraping.
Twist the new pump into place under the power steering pump bracket and seat it into place. Install the four mounting bolts that secure it to the block. Tighten them evenly.
Install the two bolts that hold the pump to the power steering bracket. Install the pulley using a screwdriver to hold the bolts while you tighten them. Make sure the pulley seats squarely on the flange and does not wobble when you spin it round.
Install the belt and set it to the proper tension. Reinstall the lower radiator hose and tighten the clamp. Leave the upper hose off for the moment.
Fill the system with a mixture of antifreeze and water appropriate for your climate. I use 50/50. Fill until the fluid comes out the heater hose or the metal line. Reinstall the hose and continue to fill the system. Most Jeeps hold about two gallons when the water pump is removed.
Check for leaks and then install the electric fan. Tilt it into place and engage the lower tabs. Then install the two bots at the top. Connect the control wire.
Start the engine and check the belt tension and check for leaks. Recheck the coolant level after the engine has been heat cycled.