What Is Car Water Pump? – Working and Uses

What is A Car Water Pump?

Your car’s water pump takes water from the radiator and moves it through the motor back to the radiator, where the cycle begins again. It makes sure your motor remains at a constant temperature, no matter the weather.

The water from the radiator heats up as it makes its way through the motor. It needs the water pump to return it to the radiator, where it can cool down. Otherwise, your engine would overheat.

what does a car water pump do?

A water pump is a vital part of your car, truck, or SUV’s cooling system. Its primary purpose is to continually circulate coolant from the radiator to the vehicle’s engine block to prevent overheating. Modern water pumps are much more robust, but there is still a chance they could fail after many years or miles.

Typically, a bearing on the pump may go bad, or the pump develops a leak, which can cause serious damage to the vehicle’s engine if not attended to. Luckily, there are ways to know that your water pump may be failing in advance.

How Does a Water Pump Work?

A vehicle’s water pump is a belt-driven pump that derives its power from the engine’s crankshaft. Designed as a centrifuge, the water pump draws the cooled fluid through the pump’s center inlet from the radiator. It then circulates the fluid outward into the engine and back into the car’s cooling system.

In most vehicles, the engine turns the water pump’s belt, which turns the water pump’s axle.

  • The axle is connected to a series of vanes, which also rotate with the axle
  • The turning motion creates suction and pulls the water from the radiator

When the water reaches the pump, centrifugal force throws it against the pump’s outer walls and down a drain to the engine block. The water travels through the cylinder heads and drains back to the radiator, where the process starts again.

How can a car water pump break?

A grinding or rumbling noise indicates worn water pump bearings. Although it may be possible to renew the bearings, the chances are that the seals will be worn as well. For peace of mind, the complete pump is normally replaced – they’re not that expensive.

A coolant leak from the water pump could be a sign that the shaft seal or the gasket that sits between the pump and the engine has failed. If it’s the shaft seal the entire pump will need to be replaced, but if it’s the gasket the pump can be removed, a new gasket fitted and the original pump replaced.

Some modern water pumps have plastic impellers (fan blades) and these sometimes break. This leads to vibrations which in turn cause the pump to fail. It’s also possible for the impeller to become loose on the shaft, so although the impeller looks OK, it doesn’t pump anything!

How can I make my car water pump last longer?

Bear in mind that the pump is often driven by the timing belt. In which case the belt must be renewed at the same time as the pump. In fact, some manufacturers recommend the pump is renewed whenever the belt is replaced.

Maintaining a healthy water pump is easy: you need to make sure the engine coolant is in good condition and has the correct specification and amount of antifreeze. The latter stops the water from freezing in cold temperatures and acts as a rust inhibitor, preventing small particles from breaking off inside the engine and wearing the pump’s parts.

Car Water Pump

Symptoms Of a Bad Water Pump

The most common symptom of a bad water pump is coolant leaks under your car together with an overheating engine. You can sometimes also hear a squealing noise coming from the water pump if the bearings are bad. Unstable engine temperature is also common.

While these are just the common signs and not all of them, it’s a good start. Here is a more detailed list of the 6 most common symptoms of a bad water pump.

1. Leaking of Coolant

When the water pump goes bad, it may leak from the axle sealing or any gasket. The water pump uses gaskets that ensure the coolant stays sealed and that the flow of water is uninterrupted.

However, these gaskets can deteriorate and become completely useless in time, causing the coolant to leak out from under the water pump.

If you have a puddle of water or coolant below the front end of your car, you are probably looking at water pump failure, and so you need to go to a mechanic.

2. Squealing Noise

When the water pump goes bad, it may leak coolant into the bearings of the water pump, which will dry out the bearings of grease and therefore create a squealing noise when the engine is running.

If you hear a squealing noise from the water pump you should replace the water pump as fast as possible, as it may be fatal to your engine to keep driving – especially if the water pump is driven by the timing belt.

3. Water Pump’s Axle lose

There is a serpentine or timing belt making the water pump turn and pump coolant. If the water pump axle gets worn out it may cause a loose belt. If this happens, you are looking at a complete replacement of the water pump.

To feel if the water pump’s axle is loose, you have to remove the serpentine or timing belt. If you feel any play in the axle, replace it imminently.

4. Overheating Engine

The water pump’s primary job is to pump around coolant in the system to cool the engine. If the water pump fails somehow, you will see the temperature gauge rising on the dashboard.

This can happen due to several reasons, such as thermostat failure or short electrical wiring, but you should always get it checked out by a certified mechanic. Otherwise, you are looking at widespread damage to the head gasket, the cylinders, and pistons, all of which can reduce the overall life of your engine.

5. White Smoke from The Radiator

If you see white smoke coming out of your radiator, you are looking at a clear sign of water pump failure. The steam in the radiator is produced from an overheated engine, which can happen if the water pump is not working perfectly.

When faced with this problem, it is better to stay safe and stop driving, wait for the engine to cool down, and try to reach your mechanic.

6. Unstable Engine temperature

You can also notice intermittent problems with the water pump as the impeller might be loose on the water pump axle.

This will cause the car to overheat sometimes and sometimes work fine for a couple of weeks. It’s always better to be safe than sorry when it comes to water pumps, though, so replace it if you think it’s bad.

My car’s water pump is leaking. What do I do?

If your water pump is leaking, you have an issue. How major of an issue depends on the severity of the leak.

Water pumps typically leak from two different places: the shaft seal or the water pump gasket. Either way, there’s something wrong, and your water pump needs to be replaced.

There are some stop-leak products out there that you pour directly into your radiator that can (possibly) seal or slow the leak. If you go this route, keep in mind these products are an only temporary fix and not permanent solutions.

In short, if your water pump is leaking, we recommend taking it to a mechanic to have it replaced. Your engine will thank you.

How Much Is a Water Pump?

The cost of replacing your water pump depends on the make of your car. Even the particular model can affect the cost.

In addition, there are two types of water pumps: belt-driven and electric.  Typical belt-driven water pumps aren’t that expensive, but electric ones can get pricey, which will obviously drive up the cost.  Your owner’s manual should be able to tell you which kind you have.

Another thing to keep in mind is that some water pumps are easier to get to than others. The more your engine needs to be taken apart to access the water pump, the higher the labor costs.

Taking all of these points into consideration, you can expect to pay anywhere from $400 to $800. Of course, shopping around to get a few quotes is your best bet to get the best deal.