What Does a Water Pump Do in a Car?

The water pump in your car moves coolant from the radiator to the engine. This process repeats continually and prevents your vehicle from overheating.
Written by John Davis
Reviewed by Melanie Reiff
A car’s water pump moves coolant from the radiator to the engine and back. This process repeats continually. The water pump is part of the system responsible for keeping your engine at a constant temperature, preventing it from overheating. 
Your vehicle comprises various parts large and small. Some of them are absolutely integral to its function, while others only serve to increase its user-friendliness. The car’s cooling system is one component necessary to keep your vehicle running correctly—but just how does it work?
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What is a water pump, and how does it work?

The water pump in your car is responsible for moving coolant through the radiator and hoses, engine block, and cylinder head. This process ensures that your engine remains at an optimal operating temperature and doesn’t overheat.
Automotive water pumps use impeller blades and centrifugal force to propel the coolant through the system. The pump gets its power from your car’s engine using a drive belt or serpentine belt. The belt connects to the water pump pulley and turns an axle, which, in turn, causes the impeller blades to rotate, creating the suction necessary to pull the coolant from the radiator. 

What are the symptoms of a bad water pump in a car?

As it’s such an essential part of your car’s cooling system, you need to be aware of the signs of a bad water pump. If this vital component fails, it could spell disaster for your engine. Some of the most common symptoms of a faulty water pump include the following:

Coolant leaking

While leaking engine coolant isn’t always a sign that your water pump is bad, it’s definitely not something you want to ignore. If you notice a puddle of coolant beneath your car, it could indicate that your water pump is damaged or failing. That’s because the water pump contains several gaskets and seals that can dry out over time, leading to fluid leaks.
If you notice coolant leaks, the smartest thing is to take your car to the repair shop for further diagnosis.

Overheated engine

A classic sign of a failing water pump is an engine that overheats. If your car’s temperature gauge is consistently rising, it could be because the water pump is failing to send the necessary coolant to keep the engine cool. This is a serious problem that can result in severe engine damage

Rust or coolant deposit build-up

A small coolant leak around your water pump can result in a build-up of corrosion, rust, or mineral deposits. Sometimes, this is the result of using the wrong type of coolant. Other times, it’s caused by small leaks that result from bad gaskets or cracked hoses. 
If you notice any build-up or rust around your vehicle’s water pump, it’s probably time to take a trip to the repair shop.

Unusual noises

Unusual sounds, like a grinding or whining noise, can be signs of a failing water pump. Faulty or loose belts typically cause whining noises coming from the engine bay. 
One of the things that can damage your engine drive belt is a loose pulley on your water pump. Sometimes, you can fix this problem by tightening the pulley. Other times, a new water pump might be necessary.
On the other hand, low grinding noises are often a sign of bad water pump bearings. These bearings reduce friction between the moving parts of your car’s water pump and wear out over time. When this happens, it’s best to go ahead and replace the entire pump. 
MORE: Antifreeze vs. coolant: what’s the difference?

Steam coming from the engine

If your engine temperature climbs too high, you may begin to see steam coming from under the hood. This can happen if your water pump fails completely and can no longer move coolant through the engine. 
An overheating engine is dangerous for you and other drivers. If you notice steam coming from your car while driving down the road, pull over and call for help immediately

How much does it cost to replace a water pump in a car?

Between the new pump and labor costs, you can typically expect to spend between $400 and $800 to replace your car’s water pump. 
If you’re confident in your automotive repair abilities, you can reduce this number by replacing your water pump at home—but make sure you consult your owner’s manual and vehicle repair guide first to ensure you get the right parts and learn the proper torque specs. 
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Does insurance cover a water pump replacement?

Water pumps are regarded as serviceable parts that wear out and must be replaced over time. Because of this, most insurance companies will not pay for a water pump replacement
However, if your damaged water pump results from a covered accident, your insurance policy may cover its replacement costs. 
In other words, water pump maintenance should be a part of your car care plan, just like regular oil changes and tire rotations. And you should not expect your insurance to pay for a faulty water pump unless it is the direct result of a covered crash or other covered incident. 

How to shop for affordable car insurance 

While car insurance probably won’t cover your water pump replacement, it remains an essential item for any driver. It’s not just a legal requirement in most states, but it’s also the best way to avoid losing a lot of money after a major car accident.  
But if shopping for car insurance sounds worse than replacing your water pump, don’t worry.
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All you have to do is answer a few simple questions, select the policy you like best, and enjoy the savings. The average Jerry user saves more than $800 annually after downloading the app and switching providers! 
And if you ever need some extra help along the way, Jerry’s licensed agents are standing by to take your calls and answer your texts.
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Water pumps are designed to last between 60,000 and 90,000 miles, but many can last longer. However, if your car has more than 100,000 miles, you should anticipate replacing the pump soon.
While it is possible to drive a car without a water pump, it is highly unsafe to do so. Without a functioning cooling system—which begins with a working water pump—your vehicle will quickly overheat, which can lead to catastrophic engine damage.
More often than not, a bad water pump is simply caused by the aging and deterioration of its internal parts. These pumps are not designed to last forever, so you must replace them after they wear out.
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