Without cooling system components like the water pump, your engine may be running too hot, like a volcano ready to erupt. Though an overheating engine is not exactly rare, if this happens too often, the engine may eventually seize up. To keep the engine cool and operating at its best, the pump should be in good shape, ready to shoot coolant through the cooling system. Once the pump has reached its limits, which usually takes place after around 100,000 miles, or once it has worn out for good, then this should be fixed or even replaced as soon as possible.
Signs of a water pump gone bad
Coolant leak: The old pump may crack and have a hole or eventually break its seals. To check, you can place a piece of white paper under the vehicle. If there are pools of liquid or traces of coolant, the pump may be leaking. You can also visually inspect the pump to confirm the source of leaks.
Unusual noise: Squeals from the pump are a sign of age or damage. A low-pitched grinding sound from the pump's pulley is also an indication of wear. If you hear any of these unusual sounds, the pump should be tested for quick repair or be replaced if necessary.
Poor air-conditioning: Poor air-conditioning can be an indication of a damaged or busted pump. In this case, your car's dashboard vents may fail to blow out cool air throughout the cabin.
Overheating engine: If the engine frequently overheats, then one of the cooling system parts may be failing. In this case, you may notice steam from the engine. A faulty pump may be the real problem here. One way to check for a troubled pump is by testing the pump's pulley for play. You can do this by holding opposite ends and rocking them back and forth. If you feel looseness in the pulley, the bearing may be wearing out.
Steps in replacing a bad water pump
Removing the old pump
Step 1: Use a ½-inch wrench for turning the nut and disconnecting the negative battery terminal. You don't need to remove the nut. Just keep the terminal loose.
Step 2: Drain the coolant into a pan or plastic container. To do this, use the drain valve found at the bottom part of the radiator. Make sure that the drained coolant is properly disposed.
Step 3: Detach the old pump. Disconnect the alternator, brackets, belts, and pulley with pliers. The fan, fan shroud, and pulley should be disassembled as well. Use a torque wrench for unscrewing the belts and uncoupling the hoses. Once everything's unfastened, you can pull out the old pump.
Installing the new water pump
Step 1: Remove any trace of gasket material on the surface where the new pump will be mounted.
Step 2: Dab a small amount of gasket sealant on the mounting surface and the gasket's engine side. Leave this for about 10 minutes.
Step 3: Mount the new pump for installation. After installing the pump and gasket, put back the hoses, brackets, and other previously disassembled components. Also reattach the belts, pulley, and other connections to the pump.
Step 4: Put some thread sealant on the nuts and bolts to reinforce them and to prevent leaks. Also make sure that you top off the system with water or a preferred mixture of water and antifreeze, especially during cold days.
Step 5: Test-drive the vehicle to check for water or antifreeze leaks from the water pump after you've reconnected the battery terminal.