| Coolant leakage | From the bleed hole of the water pump | Visually check | Check leaks after about ten-minute warming up. | If coolant still leaks, replace a water pump. |
| If leakage stops, reuse the water pump (Do not replace the pump with a new one). |
| From gaskets or bolts | Check the tightening of the water pump mounting bolts. | Retighten the mounting bolts. |
| Check damage of gaskets or inflow of dust. | Replace the gasket and clean dust off. |
| From outer surface of water pump | Check the material or any cracks of the water pump. | Poor material. If any crack found, replace the water pump. |
| Noise | From bearings From mechanical seals Impeller interference | Inspection with a stethoscope | After starting the engine, check noise with a stethoscope. | If there is no noise, reuse the water pump (do not replace it). |
| If there is any noise from the water pump, remove the drive belt and recheck. |
| Inspection after removing a drive belt | After removing a water pump and a drive belt, check noise again. | If there is noise, reuse the water pump. Check other drive line parts. |
| If there is no noise, replace the water pump with a new one. |
| Inspection after removing a water pump | After removing a water pump and a drive belt, check noise again. | If there is any interference between them, replace the water pump with a new one. |
| Overheating | Damaged impeller Loosened impeller | Loosened impeller | Corrosion of the impeller wing | Check engine coolant. Poor coolant quality/Maintenance check |
| Impeller separation from the shaft | Replace the water pump. |
