Water pump – check
1. A failure in the water pump can cause serious engine damage due to overheating.
2. There are several ways to check the operation of the water pump while it’s installed on the engine. If the pump is defective, it should be replaced with a new or rebuilt unit.
3. Water pumps are equipped with weep or vent holes. If a failure occurs in the pump seal, coolant will leak from the hole. In most cases you’ll need a flashlight to find the hole on the water pump from underneath to check for leaks (see illustration). Note: The weep hole on some models is difficult to see because of the design of the pulleys and drivebelts.
7.3 The water pump weep hole will drip coolant when the seal on the pump shaft fails (typical)
4. If the water pump shaft bearings fail there may be a howling sound at the front of the engine while it’s running. Shaft wear can be felt if the water pump pulley is rocked up and down. Don’t mistake drivebelt slippage, which causes a squealing sound, for water pump bearing failure.
5. It is possible for a water pump to be bad, even if it doesn’t howl or leak water. Sometimes the fins on the back of the impeller can corrode away until the pump is no longer effective. The only way to check for this is to remove the pump for examination (Water pump – removal and installation).