You may have heard your auto mechanic talk about a problem with overheating or a car water pump leaking, but you’re clueless. So now you’re searching, “What is water pump in a car?”
What Is a Water Pump?
A water pump, aka coolant pump, is a belt-driven device used in motor vehicles to maintain the circulation of the coolant from the radiator to the engine.
The combustion of fuel and air produces mechanical energy (motion), but aside from that, it also expels heat energy. Without a water pump to cool the system, heat can build up inside the engine and cause overheating.
Depending on the car model, the drive belt could be a fan, serpentine or timing. A timing chain can also be used in place of the belt. However, with a timing chain, the water used for cooling can end up mixing with the oil once the pump fails and cause the engine bearings to fail.
The exterior of the water pump of various cars may differ from each other, but the interior parts perform the same function and thus will be similar in construction.
What Does a Car Water Pump Do?
A car water pump keeps the temperature inside the engine at acceptable levels by dissipating heat. It is essentially the heart of the automotive cooling system, because the car water pump function is to continuously circulate the engine coolant from the radiator to the engine and back to the radiator.
Without it, you will not enjoy a comfortable ride.
What Does an Automotive Water Pump Look Like?
Car water pumps is shaped like a disc at the centre and are made of a steel-and-aluminium material. The inner part of this device is circular and has chambers. In the middle is a spindle with paddle-like protrusions radiating outwards.
Of these protrusions, one is connected to the radiator while another attaches to the engine. Once a car pump malfunctions, both engine and car will overheat, which in turn may lead to many other problems.
Where Can I Find the Water Pump in a Car?
The water pump is positioned just behind the fan belt and are usually bolted on the engine mount. In some cars, it is located on the front, while in others, it is on the side.
A hose connects it to the radiator, another set of hoses connects the pump to the engine, while a fan belt connects the pump’s central spindle to the engine output.
How Does a Water Pump Work?
The pump is powered by the engine and typically operates through a belt-and-pulley system, but a gearing chain could also be used.
It operates by applying the concept of centrifugal force. When the engine runs, the fan belt turns. The turning fan belt will then cause the axle and the connected vanes to rotate. This rotating motion creates a suction force, which pulls water from the radiator.
The massive power generated by the vanes forces the water against the exterior walls of the pump, pushing it to the engine block and the cylinder head.
From the cylinder head, water then flows back into the radiator. The cycle starts again and repeats this process over and over as long as the engine keeps on running. The thermostat ensures that the amount of water flowing through the system is enough to cool the engine.
The coolant pump can move over 7,000 gallons of coolant in an hour. At peak RPM, the pump can recirculate the coolant over 20 times in a minute. The circulation rate depends on the speed of the engine. If the engine speed is slow, the pump will also work at a lower circulation rate.
When the engine speed increases, it generates more heat. As the new conditions require more cooling, the impeller will operate at higher speeds.
Parts of a Car Water Pump
Here are the main car water pump parts:
- Housing – It refers to the shell encasing the pump and is typically made from iron or cast aluminium. Nowadays, stamped-steel is also used.
- Weep Hole – The weep hole is located in the housing of the pump. It is a small part, but it has an important role. It ensures that the leaking coolant escapes instead of being trapped. If trapped within the pump, the leaking coolant will affect other components. More about weep holes in the section below.
- Impeller – Unlike the housing, which is made from metallic elements, the impeller can be made from metal or plastic. It ensures the perfect distribution of the coolant. The rate at which the impeller distributes the coolant is dependent on the engine’s RPM.
- Seal – As the name suggests, it ensures that the coolant cannot enter the bearing assembly. Coolant leakage is mostly due to seal failure. These leaks can cause the water pump to fail.
- Bearing – The bearing assembly supports the shaft to help it achieve a continuous, controlled, and stable rotation.
- Hub or Pulley – The hub or pulley is connected at the top of the shaft. It ensures that the pump has enough power to rotate the impeller and drive the coolant through the engine.
What’s the Most Important Part of a Car Water Pump?
Of all the car water pump parts, the most important is the impeller, which has the job of circulating the coolant throughout the car. However, it only works when it operates on a sealed bearing. A leak to the seal will cause the water pump to quickly wear out.
More about Water Pump Weep Holes
Very few people know about a water pump’s weep holes. These are holes in the water pump’s casting – on the top is a weep hole that acts as air vent, allowing air to evacuate the casting system and prevent the build-up of humidity around the bearing.
It uses atmospheric pressure to keep the seal intact. There’s a lower weep hole, which allows moisture collected around the pump to drain out, protecting the integrity of the bearing.
Signs that a Car Water Pump Is about to Fail
Just like any other car component, the gasket wears out and erodes as the water pump keeps running.
- Leaking – Erosion of the gasket makes the water leak out of the hole. Leaking should be your warning sign that the water pump is failing. If this happens, you should head to the auto repair shop immediately.
- Overheating – A failing pump will cause overheating of the engine and, eventually, engine breakdown. For this reason, it is crucial to inspect the whole car cooling system. This routine task entails examining leaks and loose bearings and testing of coolant condition and belt tension.
Use a high-quality flashlight to inspect leaks in case the water pump's position is visible. While at it, you should check whether the weep hole has any wet or dry coolant residue. Also, check for any leaks in the gasket and the timing cover area.
When replacing a water pump that has failed because of loose bearing, check the fan for any damage and make sure that the tension on the belt is constant.
Finally, test the temperature protection and pH levels of the coolant, its flow as well as pressure. The coolant’s pH should be maintained in the range of 8.5 to 11 to prevent corrosion.
The water pump does a great deal of work to ensure that the engine runs well. Before embarking on long road trips, have a certified technician thoroughly inspect your car's water pump.
What Causes Car Water Pump Failure?
- Water Pump Leak – If a pump fails, it is most often because a seal failed, not because the impeller has stopped working. There are several causes to a premature seal failure, but the most common cause is high temperatures. Mechanical seals rely on spring-loaded assemblies to ensure the carbon seals remain intact. If the engine consistently overheats, it may disintegrate the rubber parts.
- Electrolysis – This is another common cause of pump failure. It creates a film or crystallisation over the seal, allowing moisture to enter the weep chamber.
- Gel-like additives – Another reason of water pump failure is the rampant use of gel additives. Not a few chemical additives on the market supposedly promoting the health of a car’s cooling system actually damage the seal around the pump.
How to Replace a Car Water Pump?
Car water pump repair will not be a feasible option once it is damaged. Getting a car water pump replacement will be the best thing to do. You may not undertake the procedure yourself – but if you’re handy, why not?
Whether you DIY it or bring your car to the pro, the basic basic steps for replacing a water pump are the same.
The idea is, you’ll know the extent of the work that your mechanic will do to replace your car’s water pump.
Replacing Your Car's Water Pump – In 9 Easy Steps
Here goes:
- Buy a car water pump replacement specified for your car. Your mechanic will help you in identifying the part specs.
- Turn off the engine and allow it to cool. Locate the car battery and disconnect the battery's ground.
- Place a drain pan beneath the engine. Drain the contents of the cooling system.
- Locate the alternator mounting brackets; loosen them to remove the drive belts. Clear any clutter or accessories out of the water pump's path. Remove the pulley, fan, and fan shroud of the engine to access the pump.
- Disconnect the hoses of the water pump. Loosen the screws and remove the water pump from the engine. Find a place for it, away from your work area. Inspect the engine block and clean it with a rag.
- Inspect the gaskets of the water pump and replace them if they’re damaged or worn out. Take the new water pump and place it exactly where you removed the old pump from. Bolt the water pump in place.
- Reconnect the water pump hoses and replace the parts that you removed. Make sure that the belts are properly adjusted to the correct tension.
- Refill the car cooling system with the correct coolant product or antifreeze.
- Plug the battery back and start your car.
In the wrecking industry, it’s quite common to hear offers of second-hand water pumps, especially if it’s super expensive like water pump for an electronic car or a BMW. My advice to you is to always buy water pumps brand-new.
If those are too expensive, you can always try place like HSY auto parts, Imparts, Welch, Unique Auto Parts for new and genuine car parts.
If you have a more mainstream vehicle, like Ford, Holden, or Hyundai, you can find cheaper options at big franchise companies like REPCO or BURSONS.
Did you find this article useful? Hope you did! You can find more where this came from – CarPart AU! Need a car water pump replacement or other car parts but don’t know where look? Request for parts here and we’ll find them for you!