A car water pump is a belt-driven mechanism that regulates the flow and control of the coolant from the radiator to the engine.

Depending on the style of the car, the belt could be a fan, a serpentine, or a timing belt. In place of the belt, a timing chain may also be used.

However, with the timing chain, the water used for cooling will end up mixed with the oil as soon as the pump fails, and the engine bearings fail. As you can see from the name, in this case, the coolant is water.

The exterior of the water pump of different cars can vary from one another. However, the interior components serve the same function and are thus identical in construction.

The water pump is situated just behind the belt of the fan. In some cars, it’s on the front, and in others, it’s on the rear. It takes the form of a disk in the middle, with arms-like elements radiating outwards.

car water pump
Car mechanic replacing water pump of modern engine

One of these arms is connected to the radiator, and the other is linked to the engine. Once a water pump malfunctions, both the motor and the car can overheat, which, will lead to many other issues.

What exactly does the water pump do in a car?

A water pump is one of the main components of the cooling system of the engine. It flows in antifreeze that absorbs some of the heat produced by the engine. Also, the pump serves to transport the antifreeze to the radiator, which in turn reduces its temperature.

The antifreeze, which is now, cooled again, returns to the water pump and the cycle begins again. Hence, this is an apparent description of how this mechanism functions which allow you to understand how essential a water pump is to your car. Okay, now that we understand what a water pump is doing in a car, how is it going to do that?

How does the water pump in a car works?

The water pump doesn’t just work on its own. Instead, the car’s serpentines belt (also known as an auxiliary or accessory belt), which attaches to the crankshaft pulley and operates while the engine is being started, supplies the power that the pump requires to do the job of holding the car coolant at an optimum temperature.

car timing belt

With the serpentine belt going, the impeller blades within the water pump will spin, essentially pushing the coolant into the different sections that require it, such as the water jacket around the engine cylinders, but the coolant doesn’t stop. Next, the hoses carry the coolant to the heater.

As this part is usually at the front of the hood, the flow of air through the radiator fins helps to cool down the liquid that absorbs heat from the engine. When the coolant has had time to get rid of some of its built-up pressures, it exits the radiator, going straight towards the water heater.

how does the car cooling system work

From there, the loop continues until you turn off the engine, which prevents the crankshaft pulley and the serpentine belt from trying to move and therefore the water pump until you drive your car next.

While it is the responsibility of the coolant and the heater acting to prevent the engine from excessive heat, the passage of the liquid through the system would not be possible without the water pump to kickstart and sustain the coolant flow across the system.ox Content

However, while it appears to be an essential part (especially compared to other parts under the hood), the water pump is necessary to keep the engine in good shape and reduce the possibility of overheating damage.

What are the main parts of the water pump?

car water pump parts

The water pump for the car includes a variety of parts; the main ones are bearings, housing, gasket, impeller, and seals.

  1. Seals
    • As the names imply, it assures that the coolant is not able to penetrate the bearing assembly. Coolant leaking is often due to sealing failure. These leaks can lead to the water pump malfunction.
  2. Housing
    • It refers to the casing that encloses the pump and is typically made of iron or cast aluminum. Nowadays, stamped-steel is still used.
  3. Impeller
    • In contrast to housing, which is made of metallic components, the impeller may be made of metal or plastic. It means that the coolant is correctly spread. The pace at which the coolant is circulated by the impeller depends on the Speed of the engine.
  4. Bearing
    • The bearing assembly helps the shaft to help achieve a constant, regulated, and steady rotation.
  5. Gasket
    • The gasket slips well into the space between the water pump and the engine. By sealing off the region surrounding the pump opening, the gasket ensures that coolant leakage is avoided. However, over time, the gasket can be weakened by rust and corrosion.

Different types of car water pumps

Water pumps with mechanical or electric drives are used in modern cars, depending on the engine concept.

1. Water pumps with mechanical drives

mechanical water pump

Water pumps with mechanical drives are incorporated either in the toothed belt drive or in the V-ribbed belt drive. The transmission ratio between the crankshaft drive and the water pump act as a fixed relationship between the crankshaft speed and the engine speed

2. Water pumps with electric drives

water pump with electric drives

Water pumps with electric drives operate independently of the engine speed. Their efficiency may be tailored to the requirements of cooling. This ensures that the working temperature is attained quickly.

As they are more functional, electric water pumps often help minimize fuel consumption.

What are the symptoms of a bad or failing water pump?

Here are some typical symptoms that indicate a bad water pump:

1. Water pump pulley becomes loose, causing a whining sound

From time to time, you could hear a high pitched sound coming from the front of the engine. This is usually induced by a loose belt that produces a harmonic humming or whining sound as it circulates.

The flexible belt is typically triggered by a pulley that has become loose or the bearings that control the water pump assembly are worn out.

If we have the bearings malfunction inside the water pump, this means that the unit cannot be fixed and will have to be entirely replaced. If you find that there is a loud moaning sound emanating from the front of your engine that rises in frequency as you drive, call the mechanic to check your car as soon as possible.

2. When car engine starts overheating

car engine overheating

If the water pump completely fails, the coolant would not be able to flow into the engine block. This results in an overheating condition which, if not immediately restored or replaced, can cause further engine damage, such as broken cylinder heads, forced head gaskets, or burnt pistons.

If you find that the engine temperature gauge is running high on a regular basis, this is more likely than not to be a water pump issue. You should call the mechanic to inspect the problem and, if possible, repair the water pump.

3. When coolant leak in the front middle of a car

coolant leaks

The water pump consists of several gaskets and seals that hold the coolant in place and maintain a constant flow of coolant from the radiator to the engine.

These gaskets and seals can gradually wear down, dry up, crack or break completely. When this occurs, the coolant can spill out of the water pump and drop to the pavement, generally in the front of the vehicle and the middle of the engine.

If you discover that there is a coolant leak (which tends to be green or occasionally red in color) under the center of your vehicle, truck, or SUV, call a skilled mechanic to inspect the issue. More often, it’s a water pump leak that can be fixed before it gets worse.

How often do you need to replace a water pump?

A water pump is so necessary that it is very resistant to breakdowns. Would that mean you’re never going to need to replace it? As the water pump cooperates with the valve train, it should be regularly replaced as you replace the timing belt which occurs every few tens of thousands of kilometers or up to two hundred thousand kilometers you drive.

Can you drive a car with a leaking water pump?

Well, based on your luck, you may be able to continue running the car for weeks or months, if the pump is leaking, as long as you are very vigilant to make sure you add enough water in before the coolant level gets low enough for the engine to run hot.

Or maybe the pump will fail completely, and you could ruin your engine in two minutes, or even less runs it up a steep hill.

You could go a few miles on a decent road before you badly damage the overheating engine, which is long enough to create a safe spot to pull over in most scenarios.

How much is a water pump for a car?

 The cost of a water pump is arbitrary to make, model, year, motor, type of vehicle (car, truck, etc.). Suppose it’s a new pump or a refurbished pump, etc. They will actually vary from around $30 to $200 or $250 for ‘everyday cars’ to $1800, and even more for high-end/exotic cars.

However, it is one of the most crucial external engine components that essentially hold the engine alive, running in a safe and optimum temperature range following the thermostat.

How much to replace the water pump in the car?

car water pump replace

Currently, the pump itself is affordable, although that relies on the kind of car you drive and the automotive repair shop you go. This does not mean replacement is just a new pump plus a few additional per cents.

This is because it takes some time and intensive operations to replace the old pump and add the new pump. In other words, the amount that you pay is primarily the labor costs itself.


Water pumps play a significant role in your car’s cooling system and continuously pump coolant and water into the engine. The blades on the pump, controlled by the drive belt, allow the coolant to flow into the engine’s cooling system. However, while the water pumps are made to last, they often break down and need to be checked regularly.

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