The water pump in a Isuzu Rodeo is used to push the coolant from the engine to the radiator. The water pump contains an impeller that pushes the coolant through the pump and to the radiator. Once the water pump breaks down, it will no longer be able to hold coolant and leak it out through the weep holes on the pump. Troubleshooting the pump will take a matter of minutes to determine if it is bad or good. A pressure tester will be required to test the pump. The tester can be purchased or leased at most automotive parts stores.
Park the truck on a flat and level surface. Ensure the truck is turned off. Take the keys out of the ignition and let the truck sit for an hour for the radiator to depressurize.
Twist the radiator cap off counterclockwise by hand and place it to the side. Inspect the level of the coolant. If it is low, fill it up with anti-freeze or water.
Twist the end of the pressure tester on to the radiator where the cap was previously. This will create a seal to push the coolant through the system.
Pump the pressure tester to 15 psi. The gauge on the end of the tester will indicate the correct pressure.
Watch the water pump located directly above the main shaft. Inspect for coolant to leak out. If coolant is leaking out from around the water pump, it is faulty.
Twist the pressure tester cap counterclockwise to release from the radiator slowly. Replace with the radiator cap.
