The water pump on your vehicle is the heart of the cooling system. If the pump fails and stops circulating coolant, your engine will stop soon thereafter. The two main ways a pump fails are leaks and seizure. Failing to properly maintain your cooling system can lead to both, so make sure you keep up on your scheduled maintenance. If you begin having cooling issues, it is best to have a trained technician inspect your cooling system. However, there are some simple checks you can make yourself, beginning with the water pump.
Put your safety glasses on, raise the hood, turn on the flashlight and look down at your water pump. It is best to do this initial examination when the engine is cold. You will also need to crawl underneath to look at the underside of the water pump during the inspection.
Visually inspect the weep hole on the pump. The weep hole is about the size of a small pencil eraser and when the main water pump gasket begins to fail, coolant will begin to dribble from the weep hole. Replace the water pump if you see any signs of leaking from the weep hole. If not, move on to step three.
Inspect for any wetness directly below the water pump. Dirt often collects on under-hood leaks, so if you do not see any signs of wetness, inspect for any dirt accumulation that appears greater than surrounding areas.
If you see any signs of wetness or dirt accumulation, you may have a leak. If you do not see any signs of leakage, move on to step four.
Start the engine and let it warm up. Carefully squeeze the top radiator hose periodically. If the hose never warms, either your thermostat is not opening as it should or the water pump is not circulating the coolant. In either case, it is best to replace the thermostat and perform this step again. If, after installing a good thermostat you still have a cold upper-radiator hose, replace the water pump.
It is advisable to flush your cooling system, replace the thermostat and replace the serpentine belt every time your vehicle suffers a coolant leak. While doing these extra things may seem unnecessary at the time, they will prevent you from having related issues in the immediate future.
Never open a hot cooling system. Coolant temperatures can easily exceed 93.3 degrees C. The engine cooling system is also pressured during engine operation. Opening a pressurised system with 200 degree coolant inside can result in serious injury or death.