To run cool on those hot summer days, your engine needs to have a constant flow of coolant from the radiator through the engine. The water pump is the main component responsible for maintaining this flow.
When it works properly, your car will maintain a constant operating temperature, run smoothly, and get you everywhere you need to travel. If the water pump fails or wears out, it can lead to complete engine failure.
When the water-cooled (as opposed to the air-cooled) engine was introduced, many automotive experts believed that the water pump’s cooling pump, circulating through the engine block, was just as important to protecting the engine as oil.
This philosophy holds true even though technology has improved over the years to create more efficient cooling systems in today’s modern automobiles.
What Is a Water Pump in a Car?
In short, the water pump keeps coolant flowing through the engine block, radiator, and hoses to maintain a proper operating temperature.
Your car’s water pump is key to making the entire system work. It’s an impeller pump and is usually buried under the timing belt cover on the side of the motor. The blades on the pump allow the coolant to flow through the engine and back to the radiator to be cooled by a forced air cooling fan.
What Does a Water Pump Do in a Car?
An impeller blade (a rotor that increases fluid pressure and flow) and centrifugal force transports chilled water into the motor. As soon as the water has run around the engine, it goes through hoses to the radiator, where the water is cooled by the movement of air over the fins of the radiator.
Then it leaves the radiator, goes back into the water pump, completes the cycle and starts over. When the water pump is doing its job, the engine should be able to maintain a normal, constant temperature.
What Makes Water Pumps Go Out?
Worn water pump bearings. If the straps are loose enough, they can lose their grip and fall off.
Water pump leaks. This is a sign that seals have failed. If the shaft seal is the cause, the entire pump must be replaced. If it’s just the gasket, you might not need a brand new pump.
Defective fan blades. Serpentine belt driven water pumps with plastic flange blades can break and cause vibrations, causing the water pump bearings to fail.
Symptoms of a Failed Water Pump
Here are some common symptoms that hint towards having a bad water pump:
1. Coolant leak at the front-center of your car
The water pump consists of several seals that contain the coolant and ensure an even flow of coolant from the radiator to the engine. Eventually, these seals and gaskets wear out, dry out, crack, or completely break.
When this happens, coolant leaks out of the water pump and falls to the floor, usually in front of your car and in the middle of the engine. If you find that coolant is leaking in the middle of your car, truck, or SUV, contact a professional mechanic to investigate this problem.
Most of the time it is a leak on the water pump that can be fixed before it gets worse.
2. Water pump pulley is loose and making whining sounds
From time to time you may hear a high pitched tone coming from the front of the engine. This is usually caused by a loose belt that creates a harmonic hum or wail as it circulates.
The loose belt is usually caused by a loose pulley or the bearings that operate the water pump assembly wear out. As soon as the bearings in the water pump fail, the device can no longer be repaired and must be completely replaced.
If you notice a loud wail being heard from the front of your engine, the volume increasing as you accelerate, contact a mechanic as soon as possible to inspect your vehicle.
3. Engine is overheating
If the water pump fails completely, it will not be able to circulate coolant through the engine block. This creates an overheating situation and, if not quickly repaired or replaced, can cause additional engine damage such as cracked cylinder heads, printhead gaskets or burned pistons.
If you find that the engine temperature gauge runs hot frequently, it is most likely a problem with the water pump. You should contact a mechanic to investigate this problem and replace the water pump if necessary.
4. Steam coming from your radiator
If you finally find steam coming from the front of your engine or stalling while you are driving, it is an immediate sign of an overheated engine. As explained above, when the water pump is working properly and water is circulating to a working radiator, an engine will maintain a constant temperature.
If you notice steam coming from the front of your engine, you should drive to a safe place and contact a mechanic as soon as possible. Driving an overheated engine is never a good idea. So if you need to contact a tow truck to get the car home, you can save significant costs in the short and long term. This is cheaper than completely replacing the motor.