Mercury FOAZ-8501-A Water Pump Assembly

To check a water pump, warm up the engine and squeeze the upper radiator hose. A pressure surge indicates a working pump. Look for coolant leaks from the pump's weep hole, which suggest immediate replacement to avoid shaft bearing failure. Listen for noise from the pump during operation, as this also indicates bearing failure and need for replacement. Check for bearing wear by trying to move the pump pulley; any movement means the pump should be replaced.