The water pump forces coolant into the cooling system of your 2003 Ford Ranger. If it's going bad, the water pump may start to rumble, leak coolant and eventually cause the cooling system to fail. Because the cooling system is under pressure, it's not recommended for novice mechanics to replace the water pump themselves. Once the cooling system has been drained, however, the rest of the procedure is moderately challenging but an approachable task.
Discharge the air conditioning system at a certified service center.
Use pliers to remove the negative wire from the truck's battery.
Drain the cooling system by manually pulling out the radiator then unscrewing the plastic cap on the bottom of the radiator with a pair of pliers.
Use pliers to remove the reservoir hose from the radiator.
Remove the screws that hold the fan shroud in place with a socket wrench then push the shroud towards the engine block.
Use a socket wrench to remove the screws holding the fan assembly to the water pump belt hub.
Remove the fan assembly.
Use a socket wrench to remove the drive belt and pulley located near the end of the pump shaft.
Twist the water pump hoses with a pair of pliers until they come off.
Remove the outer timing belt cover.
Use a socket wrench to unscrew the bolts holding the water pump in place. Remove the water pump.
Clean the water pump compartment and the new water pump with acetone.
Apply RTV silicone to the water pump and the surface of the engine where the water pump attaches. Bolt the new water pump into place.
Reinstall the components that were removed by reversing the above instructions.
Refill the cooling system.
Run the engine and check for leaks.
