Symptoms of a Bad Water Pump

An engine creates immense amounts of heat while it’s running. It’s the cooling system’s responsibility to carry that heat away from the engine and disperse it into the atmosphere. One of the key components in the cooling system is the water pump, by what does a car water pump do? Its job is to circulate coolant that absorbs heat from the metal components so it can be cycled to the radiator where it’s transferred to outside air.

Water pumps can fail, and when they do they put your engine at risk of a severe issue or a complete failure if it’s left unattended. A failed head gasket due to overheating, for example, can cost you well over $1,000 to repair at a shop, and even fixing it yourself will cost several hundred dollars in parts. Luckily, a bad water pump will usually exhibit symptoms ahead of time before any serious damage is done. And a water pump on its own is much more affordable in most cases but can vary widely, ranging from under $30 to more than $800.

Here are signs of a bad water pump that you should watch for.

Signs Your Water Pump is Failing

Leaking coolant

A coolant leak can indicate many failures, but if it’s coolant on the front of the engine, it’s often a water pump leak. It’s possible that the water pump gasket where it mounts to the engine is what’s leaking, but it could also be the seal on the water pump shaft. Regardless, leaking coolant on the engine that drips to the ground is an indicator that is serious. Replacing the water pump and gasket should be in the plans.

For minor leaks, you’ll notice a white trail of residue where it drips down the front of the engine, tinged with the color of your coolant. The leak may never reach the ground because the heat from the engine dries the coolant on the metal surfaces. Changing the water pump might also require changing the timing belt, the water pump pulley, the serpentine belt, or other engine seals and gaskets.


If your engine is overheating, it’s a sign that the heat generated from combustion isn’t being transported to the radiator to be cooled. It can be due to several things such as:

  • An air pocket or airlock in the cooling system that prevents coolant from circulating, potentially due to a water pump leak. 
  • The fins on the water pump impeller have been sheared off by debris or freezing, 
  • The shaft is seized due to corrosion or bearing failure.

Overheating is a serious condition, and if you see the temperature gauge spike or have a warning message on your instrument cluster, stop your car as soon as possible and shut the engine off until it cools down. Repeatedly overheating your engine is a surefire way to cause lasting damage such as a blown head gasket, warped cylinder head, or even seizing the engine.

Squealing noise

A squealing or chirping noise from the front of the engine can also be an indication of a failing water pump. It can sound very much like when a serpentine belt is making noise, and in many cases, that’s because it is. Additional resistance from the water pump can cause the belt to slip along the pulley, usually with a rhythmic cadence that’s relative to the engine’s RPMs. 

Again, the cause is usually a worn shaft bearing. In some cases, the water pump can maintain this type of operation for weeks or months, or even longer, or it could fail immediately after by seizing up. While it’s one of the early signs of a bad water pump, it should be taken seriously, even if the noise comes and goes.

Whining noise

For water pumps on cars, the belt-driven or chain-driven pulley spins a shaft that turns an impeller inside the pump. If the symptom is a whining noise that varies with engine RPMs, it might not be an internal problem at all. Rather, a whine often indicates that either the belt isn’t tight enough or the pulley is damaged. 

It might be surprising to hear that a pulley could be the cause, but it can happen. The pulley can crack between the bolt holes, and as a result, it doesn’t run true. It’s usually caused by rust on the pulley, so it’s mostly an issue on older cars. 

For some vehicles, water pump pulleys are part of the assembly while for others, they can be replaced separately. 

Water pump corrosion

If you’re experiencing bad water pump symptoms, it can be due to corrosion. Inside the pump, contaminated or improperly mixed coolant can contribute to corrosion on the impeller. One the exterior, corrosion can cause issues with the belt slipping on the pulley. And in some cases, visible corrosion or buildup on the water pump itself can indicate it’s failing with no other symptoms at all. 

Cost to replace car water pump

If your water pump is bad, deal with it right away. Postponing the repair often leads to more expensive repairs at inconvenient times. Along with the cost of a water pump that averages between $150 and $250 for most modern cars, you’ll likely need coolant and gaskets. It’s also a good time to check the serpentine belt condition and replace it if necessary. 

If it’s a job you aren’t prepared to tackle, expect labor at a professional mechanic to add a couple hundred dollars. 

Find your new car water pump at AutoZone. You’ll find What It Takes To Do The Job Right along with advice from trustworthy associates.

FAQ for a Bad Water Pump

What are 3 ways you can tell if a water pump is bad?

Leaking or residue from the front of the engine, overheating, and whining or squealing noises from the engine can indicate a bad water pump.

How do I know if my thermostat or water pump is bad?

If your engine temperature is climbing higher than normal, you see steam from under the hood, or there’s antifreeze leaking from the engine, the thermostat or water pump could be to blame

How can you tell if your water pump is working?

If you don’t hear any noises from the water pump area when the engine is running, the coolant level is sufficient, and the engine temperature is normal, likely the water pump is fine.

When replacing a water pump, what else should you replace?

It’s a good idea to replace the serpentine belt and flush the coolant when you’re changing the water pump. If the water pump is driven by the timing belt, consider changing the timing belt and tensioner if it’s nearing the replacement interval.

What sound does a failing water pump make?

A bad water pump can make whining, chirping, or squealing noises.

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