Automobile Water Pumps: What They Do, How They Work, and When You Should Replace Yours

What Does a water Pump Do In a Car?

If you've ever looked under the hood of any vehicle, you'll notice several different parts and components. For those who are familiar with the mechanical aspects of cars, understanding how the parts come together to operate and drive might be simple, but for others, the different names and purposes can be confusing.

For example, all vehicles, from a Ford truck to a Toyota SUV, will have a water pump under the hood. While small in comparison to other parts, like the engine, this little piece is no less essential to keeping your car in functioning shape and running at its best. So what does a water pump do in a car?

The Role of a Water Pump

If you've ever done maintenance on your vehicle before, you probably took some time to let the engine cool down a bit after running before getting to work. Even if you're not the DIY car repair type, it's probably not a surprise to you that your vehicle gets pretty heated under the hood while you're driving, with the moving parts building friction and burning gasoline to boot.

While car manufacturers work to design and build engines and other durable components, they can still only stand up to so much pressure and work before they wear down. Excessively high temperatures under the hood are one of the potential issues that can overheat car components, making them nowhere near as long as they would have otherwise.

Countering this concern is where water pumps come in. This part helps push coolant throughout the:

●  Engine block

●  Radiator

●  Hoses

Without this coolant cycling throughout the car, the engine block could quickly overheat, potentially causing damage that requires expensive repairs to fix. The water pump in your vehicle is responsible for powering the cycling of the coolant to all these different components of the car, helping everything work at optimal temperatures.

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How Does a Water Pump Work?

Okay, so now that we know what a water pump in a car does, how does it do it? For starters, this part doesn't just operate on its own. Instead, the car's serpentine belt (also known as an auxiliary or accessory belt), which connects to the crankshaft pulley and runs while the vehicle is started up, provides the power that the pump needs to do its job of keeping the car at an optimal temperature.

With the serpentine belt running, the impeller blades inside the water pump can turn, effectively making the coolant move through the various pieces that need it, such as the water jacket surrounding the engine's cylinders. But the coolant doesn't stop there.

The hoses next take the coolant to the radiator. Since this component is usually at the front of the hood, the movement of air through the radiator fins helps to cool down the liquid that has absorbed the heat from the engine.

Once the coolant has had time to get rid of some of its built up temperatures, it leaves the radiator, heading back towards the water pump. From there, the cycle continues until you turn off your vehicle, which stops the crankshaft pulley and serpentine belt from moving—and thus the water pump—until the next time you drive your car.

While it's the properties of the coolant and the radiator that do the work in keeping the engine from overheating, the movement of the liquid throughout the system wouldn't be possible without the water pump to kickstart and maintain the flow of coolant throughout the system.

As such, while it appears as a simplistic part (especially in comparison to other pieces under the hood), the water pump is essential for keeping your engine in good shape and reducing the risk of damage from overheating.

Signs That Your Water Pump Needs Replacement

Since not having a working water pump could potentially lead to your engine overheating (and thus needing expensive repairs), it's helpful to know how to recognize the warning sign that your water pump is nearing the end of its lifetime. The sooner you catch the symptoms, the fewer issues you'll have from additional damage.

Look out for these warning signs.

Leaking Coolant or Fluids

Your water pump has several seals and gaskets to help maintain the flow and to help keep the coolant in your car where it belongs instead of spilling out all over the roads. Over time, they will wear down and potentially break, causing coolant to leak out.

If you see a puddle beneath your car that is green or red, then it is likely coolant, and it's time to seek repairs. Note that some leaks are slow, and while they don't spill onto the road, they do build up a layer of gunk on the pump, also potentially causing rust.

High Pitched Whining Noises from the Water Pump Pulley

Anytime you may hear an unfamiliar sound from your car, it tends to be a warning sign for a problem. Regarding water pumps, the pulley and serpentine belt will sometimes start to whine, and it's especially prevalent when accelerating. Grinding and growling noises can also indicate problems, but they tend to show bad bearings rather than loose belts.

While you can fix the noises by adjusting the belt or tweaking the bearings for a better fit, sometimes these systems have worn down enough to justify replacing them.

Overheated Engine

While an overheated engine is what you want to prevent, it can still happen. The best way to keep track of this is to pay attention to the engine temperature gauge. If it regularly shows that the engine runs hot, you should have a mechanic take a look to see if replacing the water pump will help the problem.

Steam Coming from Your Radiator

Another clear sign that your engine has started to overheat is if you can see steam coming out of your engine. If this happens, you need to immediately pull over to a safe spot and turn off your vehicle. In this situation, it's much better to have a tow truck pick up your car to take it to a mechanic.

Though you may be able to continue to drive in this scenario, if you see steam, then your engine has already overheated, and continuing to drive will cause more damage—instead of replacing just the water pump, you may have to purchase an entirely new engine, which will cost much more. It's much better to stop driving, so you have the chance of the less expensive option.

How Long Does a Water Pump Typically Last?

Since a water pump has a significant impact on the performance of your car, it's a part that can last for a while. Since it works with the timing belt, the usual recommendation is to replace the water pump at the same time as the timing belt, since they're both accessible in the same area of your engine and you can save on labor costs by having the two services done at once.

While there will be some variance depending on the make and model of your vehicle, most timing belts last between sixty- to ninety-thousand miles; for the most part, you can expect your water pump to last this long as well, barring any unfortunate issues.

If you own or purchase a used vehicle, you can use a vehicle history report to find when the last timing belt and water pump service happened and use that information to plan your maintenance.

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