Symptoms of a Failing Water Pump

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A proper functioning water pump is essential to keeping your engine healthy. Engines give off lots of heat. In order for the engine to function properly, this heat needs to be transferred from the metal engine components to the coolant. The coolant will then move to the radiator. The fins on the radiator will transfer the heat from the coolant to the air around the vehicle. In order for the coolant to do its job, it needs a water pump. The water pump is what forces the coolant through the engine block and to the radiator. It is very important to recognize the symptoms of a failing water pump because a faulty water pump will cause the engine to overheat, and it could even cause total engine failure.

A water pump uses an impeller to move the coolant through the engine.

Although it is called a water pump, the water pump is actually pumping coolant 50% antifreeze and 50% water. Unlike the fuel pump, the water pump does not use gears, rather it uses an impeller. The impeller traps the water between its blades and the impeller housing. As it rotates, the impeller will force the coolant through the cooling system.

The water pump is usually located on the front engine block or timing chain cover. The pump is driven by a serpentine belt that is connected to the crankshaft. As the engine runs it will spin the water pump forcing the coolant through the engine to the radiator via the opening in the thermostat. Now that we know a little bit about the water pump, we can discuss the symptoms of a water pump failure or issue.

1. Leaking Coolant

The water pump has multiple gaskets and seals which keeps the coolant leaking out. Over time these seals and gaskets can wear out. This wear can occur because of the thousands of heating and cooling cycles the gaskets and seals go through. If your water pump is leaking you will most likely notice drops of coolant underneath the car near the front of the engine. Coolant can look like water on the ground, but it is actually green or orange in color. If you notice a puddle on the ground at the front of the engine that turns out to be coolant, inspect the outside of the water pump as that is the most likely culprit.

2. Overheating Engine

There are quite a few possible causes of engine overheating, and a faulty water pump is one of them. Water pump failure can be caused by internal leakage around the impeller blades. This failure is caused by the pump’s inability to move enough coolant through the engine causing overheating. Overheating is serious issue to engine health. It can cause: warped cylinders, blown head gaskets, and much more damage. However, overheating can also be caused by stuck closed thermostat. If your vehicle is overheating and you’re not sure if its the water pump or the thermostat, check out our article on thermostats here.

3. Whining noise from Front of the Engine

Whining noises in engines usually have to do with rotation. The on the outside of the water pump housing is a pulley. The pulley is driven by a belt which connects to the crankshaft. A loose or worn pulley will make a whining noise. This whining noise is very obvious. It won’t go away with increased revs, in fact it will get worse.

The pulley loosening can be attributed to worn or failed bearings. If this is the issue you are experiencing you will most likely have to get a brand new water pump as few places will replace just the bearing. However, its not all bad news as water pumps commonly last over 100,000 miles and you likely won’t need to replace it again if the cooling system is properly maintained. If you hear whining noise from your engine, you should have it checked out right away. A faulty water pump pulley could eventually cause the pump to lose its pumping power and overheat your engine.

4. Steam coming from under the Hood

Steam coming from the engine bay is never a good sign. In most cases the issue is with the engine’s cooling system and the engine has overheated or is about to. If you see steam coming from your hood, be sure to pull over immediately, and do not drive the car any further. Driving an overheating car can severely damage or even total the engine.

Now since the water pump plays such a crucial role in the cooling system, it could be responsible for the steam coming from the engine. If the water pump is not circulating enough coolant through the engine, the engine will transfer its heat to the small amount of coolant moving through the engine. This smaller flow of coolant will heat up much more than it should possible creating steam. The engine won’t be able to transfer all of its heat to the inadequate flow of coolant, and it could cause serious damage to the engine internals.

5. Mixing Different Coolants

While it is not necessary one of the symptoms of a failing water pump, it is worth discussing. Mixing different types of coolant in your vehicle can and will cause serious problems. Mixing coolants together causes the different coolants to “gel” together. The water pump is unable to push this “gel” like substance through the cooling system since it isn’t a fluid. Lack of coolant flow through the engine will cause overheating. However, it won’t just cause overheating, mixing coolants can destroy your cooling system too including your water pump. Always be sure to check your owners manual to make sure the coolant you use or add to your engine is compatible with what’s already inside.

What if Your Car has these Symptoms

In conclusion, always pay attention to engine temperature gauge. If you notice overheating, be sure to pull over in order to avoid damage to internal engine components. If you notice any odd whining noises along with overheating the water pump pulley is the most likely culprit. As with any car issue be sure to address the problem sooner rather than later. Waiting to fix an issue can give the problem time to create more damage and wreak havoc on your vehicle. If you are experiencing any of these symptoms, have your vehicle inspected by a certified mechanic as soon as you can.