In the engine running, with the stethoscope against the pump shell, while changing the engine speed, pump bearing wear limit or lack of oil, you can hear sand, sand, sand noise;If the bearing is loose in the pump housing housing, there is a slight crash sound.

Pump abnormal sound is generally pump shaft bearing wear, loose or lack of oil, pump shaft retaining ring is not installed or not installed, bearing channeling, impeller back and water pump cover rub and the resulting pulley and fan impeller shaking sound.Push the fan blade by hand and inspect the pump shaft. If you can feel excessive axial and radial clearance, it is proved that the bearing is too worn or loose and should be removed for maintenance.

In automobile engine cylinder block, there are multiple for cooling water circulation channel, and placed in the front of the car radiator (commonly known as water tank) through the water pipes connected to form a large water cycle system, outlet on the engine, equipped with a water pump, driven by fan belt, within the engine cylinder block water heat pump, the pump into the cold.

Beside the water pump and a thermostat, cold (car), when the car has just started not to open, make the cooling water without water tank, only within the engine cycle (commonly known as small cycle), momentum motivation above the temperature of 95 degrees, is opened, the hot water is pumped into the tank engine inside, when the car on the cold wind blowing water tank, heat can be taken away.