The water pump on your car has an extremely important job. When functioning properly, it circulates coolant through your car's cooling system back and fourth between the radiator and the engine. If your water pump fails, you must replace it to prevent your engine from overheating, which can lead to permanent damage.
Look For Leaks
When your water pump is going bad, you will likely notice leaks. When you park your car, you may notice coolant puddles---often with a greenish appearance. You may even see coolant dripping, or notice you are replacing your coolant more frequently than you normally would.
Give a Listen
According to the website Edmunds, bad water pumps may make a noise similar to that made by a whistling tea kettle. To hear this noise, you may need to open the bonnet and listen to the engine.
Take a Whiff
If your water pump has gone bad, your car may even cast off a distinctive sulphurous odour, like rotten eggs. According to Edmunds this smell occurs when radiator coolant atomises into steam.
Watch the Heat
Watch the temperature gauges on your car carefully if you suspect your water pump has gone bad. If something is wrong with your car's cooling system, the temperature of your engine will likely rise. You may also notice other signs of excessive heat on the engine, such as a burning smell or smoke. If your engine temperature goes up and does not come back down, do not drive your car. Continuing to drive the car can become dangerous; it can also destroy your engine.
Check Your Engine
Visually inspect your engine to check whether your water pump has gone bad. According to Automedia, the presence of coolant puddles on the engine itself point to a bad water pump. Take care when checking your coolant system; the contents of the system are extremely hot and pressurised when your engine is warm.Wait until your car has cooled before inspecting your engine.