4 Symptoms of a Bad Water Pump (And Replacement Cost)

Combustion engines generate loads of heat. After all, there are thousands of tiny little explosions happening inside the engine every minute. All this heat requires an efficient cooling system, and the water pump sits at the heart of a liquid cooling system.

A water pump’s function is to keep coolant flowing through the engine from the radiator. As long as the water pump continues to function as normal, the coolant will continue to flow as it should and the engine will stay cool. If there is a problem with the water pump that impairs its ability to keep the coolant flowing, it could mean big trouble for the engine.

What Does a Water Pump Do In a Car?

A water pump circulates coolant (or “water”) through the engine. Water pumps are typically driven by the timing belt, though some water pumps are driven by a pulley from the serpentine belt instead. 

Where Is It Located?

where is water pump

The water pump is typically not visible without removing a few parts from the engine bay. Which parts are necessary to remove will depend on the vehicle. Some water pumps are hidden under timing covers that protect the cam gears. 

Water pumps that are driven from the serpentine belt are often visible when you pop the hood. These water pumps are typically easier to replace as they require less engine teardown. 

Bad Water Pump Symptoms

The water pump of your vehicle should have a long lifespan, no matter if you have a car or truck. However, that doesn’t mean the water pump can’t get worn out after a while. When it does get worn out, you will notice some obvious symptoms that will arise.

These symptoms should not be ignored because if you don’t get the water pump replaced soon, then it could permanently damage the vital components of your vehicle’s engine. Replacing a faulty water pump is a lot cheaper than repairing catastrophic engine damage so take this seriously.

Below are the top symptoms of a bad water pump.

1) Overheated Engine

prevent engine overheating

Since the water pump is what sends the coolant into the engine to keep it cool, the engine is obviously going to overheat if the water pump ever fails to do its job properly.

The temperature gauge on your dashboard should indicate the engine is getting overheated. At this point, you need to check your water pump and the other components of the cooling system.

2) Leaky Coolant

There are numerous seals and gaskets of the water pump which are responsible for securing the coolant fluid inside of the pump. If these seals or gaskets were to crack, break, or simply get worn out, then it wouldn’t be able to secure the coolant inside the pump.

Instead, there would be coolant leaking out of the pump and going all over the ground. You should see the coolant on the ground underneath the middle of the car and near the front of the car. This is definitely a problem that you’ll want to fix fast.

3) Radiator Steaming

If you’re driving your vehicle and there is steam rising out of the hood, then this is a clear indication that your engine is overheated. It should only get to this point if you’ve ignored the previous warning signs of an overheated engine, like the temperature gauge or leaky coolant.

If you don’t get your vehicle to a mechanic right away in this situation, your engine could malfunction at any moment. It would be better to have your vehicle towed to the mechanic, even if it still drives. You don’t want to take any chances.

4) Whining Noises

strange noise

The assembly of your water pump has bearings which are essential in sustaining its functionality. If these bearings were to stop working properly, there would be a loose belt in the assembly.

A loose belt will generate a whining noise or buzz as the pump tries to circulate the coolant. You should notice the sound coming from the front of your vehicle.

What Does a Bad Water Pump Sound Like?

A bad water pump may not make any noise. Some water pumps fail by leaking coolant through a weep hole. Others fail due to a faulty pulley or obstruction in the impeller.

A water pump that has failed mechanically may make a whirring or grinding noise.

Water Pump Replacement Cost

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water pump old vs new

If you have a bad water pump and you need to get it replaced, you’ll be looking to spend anywhere from $500 to $1,150. The parts cost will be somewhere from $100 to $450, while the labor costs will be from $400-$700.

The best way to save money on the replacement cost is to find a good local independent repair shop in your area which charges a low hourly rate for labor. Independent shops are usually cheaper than dealerships. 

What Else Should Be Replaced When Changing Out a Water Pump?

When changing out a water pump, it’s recommended to replace the thermostat, drive belts, radiator hoses, coolant, and any related gaskets or seals.

The thermostat regulates the engine’s operating temperature, drive belts power the water pump, radiator hoses connect the water pump to the radiator, coolant ensures proper engine cooling, and gaskets/seals prevent future coolant leaks and ensure proper pump operation.

Replacing these components along with the water pump can ensure proper engine cooling and prevent future problems and you’ll end up saving money in the long run because of lower total labor costs.

Can a Water Pump Be Bad and Not Leak?

Yes, a water pump can be bad and not leak. Some modern water pumps have plastic impellers (fan blades) that can break, leading to reduced pump efficiency and eventual failure without any visible coolant leakage.

What Causes a Water Pump to Fail?

1) Worn Bearings

The most common cause of water pump failure in cars is worn bearings. Over time, the bearings that support the impeller shaft can wear out due to normal wear and tear or lack of lubrication.

When the bearings wear out, the impeller shaft can become misaligned, causing the impeller to wobble or vibrate. This can lead to reduced pump efficiency and eventually cause the water pump to fail.

2) Damaged Seal

A damaged seal can cause coolant to leak out of the water pump or allow contaminants to enter the fluid. This can lead to overheating, engine damage, and ultimately cause the water pump to fail. Signs of a damaged seal include coolant leaks, unusual noises, and engine overheating.

3) Unbalanced Drive Pulley

A vibrating or wobbling drive pulley can cause the impeller to become imbalanced, reducing pump efficiency before eventually causing failure. This can be caused by a worn or damaged pulley, a loose or damaged belt, or a misaligned drive belt tensioner.

4) Overheating

Increased temperature can cause the water pump to fail by causing the seals to break down or the impeller to warp. This can be caused by a lack of coolant flow, a malfunctioning thermostat, or a clogged radiator.

What Happens If a Water Pump Goes Out While Driving?

A water pump that has failed while driving will quickly lead to the vehicle overheating. If your vehicle starts to overheat, pull over as soon as it is safe to do so. Continuing to drive on an overheating engine will cause further damage such as a warped head, a blown head gasket, or a cracked block.

Bad Water Pump vs Head Gasket

blown head gasket or cracked block

A bad water pump and a bad head gasket will often both make a vehicle overheat, but there are some easy ways to tell the difference between these issues. A bad head gasket can usually be diagnosed using a leak down test. A bad water pump typically exhibits other symptoms.

When your water pump is bad, the upper and lower radiator hoses may be cooler than they should be. Although some heat will transfer to the radiator through convection, this is not nearly as effective as pumping coolant through the engine.

Bad Thermostat vs Bad Water Pump

bad thermostat

A bad thermostat and a bad water pump can both cause engine overheating, but they have different symptoms. A bad thermostat can cause the engine to overheat or underheat, while a bad water pump can cause the engine to overheat and affect coolant pressure.

Other symptoms of a bad thermostat include a fluctuating temperature gauge, reduced heater performance, and coolant leaks.

If you suspect that either your thermostat or water pump has failed, it’s best to get the pros to look at it for proper diagnosis.


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