2. Warm up the engine to normal operating temperature and, without turning it off, squeeze the upper radiator hose with your hand - if a fluid push is clearly felt in it when the hose is released, therefore, the water pump is functioning properly.
Attention! Try not to touch the fan impeller with your hands!
3. The water pump is equipped with an inspection/vent hole. In the event of a seal failure, coolant begins to ooze out of the hole. Prepare a pocket flashlight and a small mirror - the hole is located on the bottom of the pump housing, directly under the assembly axis. The presence of deposits of a brownish color around the hole indicates a malfunction of the stuffing box, - slight discoloration of the surface (light gray ring) should not cause concern.
4. If the pump shaft bearings fail while the engine is running, a howling sound may occur in the front of the pump, which should not be confused with the whistle emitted by the drive belt when the tension is loosened. Bearing wear can be detected by the presence of play when the pump hub/shaft is rocked (do not forget to turn off the engine and remove the belt from the pulley before).
5. Even in the absence of external signs of wear, the final conclusion about the condition of the water pump can only be made after it has been removed and studied in more detail.