Maintenance Tips, Tricks And Hacks For Your Vehicle

8 Signs Of a Bad Water Pump




What are the signs of a bad water pump? Many different parts of your vehicle actually have ways of letting you know that they’re going to fail.

The water pump is one of them. When a water pump starts to fail, the seals go bad first and if you let it go for a long, the bearing surfaces will start to go bad and then you can have a total failure.

But, once the seals go bad, there is a little hole in the water pump that is designed to start leaking coolant past the seals. You will see coolant spraying around your engine or dripping down.

That is the first way of your water pump tells you that it is going to fail. That is not the only sign. So, what are the signs of a bad water pump?

Key Takeaway

  • Signs of a bad water pump include coolant leak, overheating engine, whining or grinding noise, steam from the radiator, seized pump and burning rubber smell, collapsed radiator hose, erratic temperature gauge readings, and coolant contamination.
  • While a water pump can technically be repaired, it’s typically more efficient and reliable to replace it entirely when malfunctioning, as a repaired pump may not perform as well as a new one; additionally, the cost of labor for replacement varies from $300 to $500, depending on the pump’s location.
  • A water pump can indeed go bad without leaking, with failures including a worn-out or broken internal impeller causing overheating, failed bearing or seal resulting in grinding or whining noises, and deterioration of the pump’s pulley or belt leading to malfunction and overheating.

What Water Pumps In Cars Do

Water pumps in cars play a crucial role in the vehicle’s cooling system. They circulate coolant (a mixture of water and antifreeze) from the radiator, through the engine, and back to the radiator.

The primary function of the water pump is to ensure that the coolant keeps moving through the engine block, cylinder head, hoses, and radiator. This continuous circulation is essential for heat exchange – it helps keep the engine at an optimal operating temperature by removing excess heat.

When the engine is running, it generates heat. The coolant absorbs this heat and carries it to the radiator where it is dissipated into the air. Without the water pump, the coolant would not circulate, leading to overheating of the engine, which can cause severe damage.

8 Signs Of a Bad Water Pump

  • Coolant Leak
  • Overheating Engine
  • Whining or Grinding Noise
  • Steam from Radiator
  • Seized water pump and burning rubber smell
  • Radiator Hose Collapses
  • Erratic Temperature Gauge Readings
  • Coolant Contamination

There are four most common signs of a bad water pump. If you notice any of these signs on your vehicle, make sure to take your vehicle to the repair shop. It’s better to fix it immediately before more damage is done.

1. Coolant leaks underneath the water pump

What Are The Signs Of a Bad Water Pump?

When the water pump is faulty due to the metal impeller being eaten by the acidic coolant or the plastic impeller structure being changed by the heat, a coolant can start leaking from the pump.

You will notice a puddle of coolant underneath your vehicle. If you do notice a coolant leak underneath your vehicle, open up the hood, and investigate further. If the water pump is faulty, the coolant should be leaking right where the pump is located in the engine.

The water pump in most cases is driven by the serpentine belt. Because it is connected to the serpentine belt, the water pump and its components like the impeller to be specific, rotate with the speed of the engine. The impeller inside the water pump can be made out of metal and plastic.

Sometimes, if the coolant gets acidic, it will eat the fins off of the metal impellers and the water pump. A new coolant can last from 2 to 5 years. If you don’t change your coolant for a long period of time it will get acidic because of the degradation of antifreeze and sulfates that are entering the cooling system.

When it comes to plastic impellers, they do an excellent job until you put it under a load where things get hot. Because of the heat, the plastic expands. The shafts inside the water pump start to spin slower than it is supposed to or are not moving at all.

2. Growling and metallic noise coming from the water pump

If you notice any growling and metallic noise coming from the engine bay, specifically from the water pump, this is a sign that the bearing inside the water pump is worn. The bad news is that you cannot replace only the bearing, you need to replace the whole water pump.

Before you replace any parts, you should be 100% positive about the source of the growling noise. Locate the water pump and touch it with a long screwdriver. If the water pump is faulty, you will hear the growling and metallic noise, but also you should feel a strong vibration through the screwdriver.

Also, you can remove the serpentine belt and try to spin the water pump pulley. See if it’s making any growling noise. Before you remove the serpentine belt, make sure to disconnect the battery.

The alternator will be close to the water pump and for safety reasons, you don’t want to fry anything. If the water pump pulley is making a growling noise while you spin it, then you need to replace the water pump.

3. Engine overheating

Engine overheating

When the water pump seal is worn, the coolant will rapidly leak. This will quickly cause the vehicle to overheat from coolant loss. Check the water pump area for any coolant leaks. Also, look underneath the vehicle to see if there is a large puddle of coolant on the ground.

After you made a positive diagnostic that your water pump is faulty and you’ve replaced it, make sure to check the cooling system components for any damage.

When an engine overheats, it is not only that engine that suffers the damage. The increased temperature can create weak spots in the radiator, the radiator hoses, and the thermostat. You should check for any possible leaks on the radiator, and the radiator hoses. Also, look for the possible stuck closed thermostat.

4. Seized water pump and burning rubber smell

Seized water pump and burning rubber smell

A seized water pump can cause the serpentine belt to slip off the pulley or it can cause the serpentine belt to burn. The burning smell is caused by the belt rubbing against the seized water pump pulley since it is not rotating anymore.

You need to locate the water pump and remove the serpentine belt. Try rotating the water pump pulley. If it does not spin, the water pump is seized. If your water pump is driven by a timing belt, a seized water pump usually causes the timing belt to skip a few teeth. You won’t be able to start your vehicle.

5. Steam from Radiator

Steam coming from the radiator is a sign of an overheating engine, which can be caused by a bad water pump. The water pump’s role is to circulate coolant through the engine and back to the radiator to maintain optimal operating temperature.

When the water pump is failing, it can’t circulate the coolant efficiently. As a result, the engine heats up more than it should. This excess heat causes the coolant in the radiator to boil and turn into steam, which is then expelled from the radiator.

6. Radiator Hose Collapses

A collapsed radiator hose can be a sign of a bad water pump. The water pump’s job is to ensure the coolant circulates properly. If the pump is failing, it may not be able to maintain the correct pressure in the cooling system.

When the engine is turned off, there’s a sudden drop in coolant temperature. This can create a vacuum effect if the radiator cap or the water pump isn’t functioning correctly. The vacuum can cause the radiator hose to collapse because the pressure inside the hose becomes significantly lower than the atmospheric pressure outside.

7. Erratic Temperature Gauge Readings

Erratic temperature gauge readings can be a sign of a failing water pump. The water pump is responsible for circulating coolant through the engine to keep it at an optimal temperature.

If the water pump isn’t working properly, it could disrupt this circulation, causing the engine to heat up and cool down irregularly.

This fluctuation in engine temperature can cause your vehicle’s temperature gauge to behave erratically. You might notice the gauge needle moving from a normal temperature reading to a high reading (indicating overheating) and back again, even if you’re driving under normal conditions.

The inconsistent flow of coolant due to a faulty water pump can lead to hot spots in the engine, causing the temperature sensor to read high temperatures, and then return to normal as the coolant eventually circulates past the sensor. This results in an erratic reading on your gauge.

8. Coolant Contamination

Coolant contamination can be a sign of a failing water pump. The water pump is a critical component in your vehicle’s cooling system, responsible for circulating coolant through the engine to keep it at an optimal temperature.

Inside the water pump is an impeller with blades that push the coolant through the system.

If the water pump starts to deteriorate or fail, pieces of the impeller or its seal may break off and contaminate the coolant. Moreover, a failing pump can cause the coolant to become dirty or contaminated with rust or debris.

This contamination can cause the pump shaft seal to fail prematurely, and it can also eat away at the impeller blades.

What Causes a Water Pump To Fail?

  • Normal wear and tear over time can cause the water pump to fail.
  • Overheating of the engine can put excessive strain on the water pump and lead to failure.
  • Improper installation or a faulty seal can result in leaks and eventual failure of the water pump.
  • Corrosion or rust can degrade the components of the water pump and cause it to malfunction.
  • Contaminants in the coolant, such as dirt or debris, can damage the internal parts of the water pump and lead to failure.
  • A broken or damaged impeller can prevent the water pump from effectively circulating coolant, resulting in failure.
  • Excessive vibration or a misaligned belt can cause stress on the water pump bearings and lead to failure.
  • Using low-quality or improper coolant can cause damage to the water pump and result in its failure.
  • Improper maintenance, such as failing to replace the coolant or ignoring signs of a failing water pump, can contribute to its failure.

How To Check The Water Pump In a Car

  1. Park the Car: Start by parking your car on a flat surface and let it cool down completely. This is important because you’ll be working near parts that can get very hot when the engine is running.
  2. Inspect for Coolant Leaks: Check under the car for any signs of coolant leaks. A failing water pump often leaks coolant from the weep hole directly onto the ground.
  3. Check the Coolant: Open the radiator cap (only when the engine is cold) and inspect the coolant. If it’s contaminated with rust or debris, the pump might be failing.
  4. Listen for Noise: Start the engine and listen for any unusual noises. A failing water pump can produce a grinding or whining noise.
  5. Check for Overheating: While the engine is running, keep an eye on the temperature gauge. If it’s higher than usual, there might be a problem with the water pump.
  6. Inspect the Water Pump: If possible, visually inspect the water pump. Look for coolant leakage around the gasket, a loose or wobbly pulley, or any visible damage to the pump.
  7. Check Radiator Hoses: Inspect the radiator hoses. If they are collapsed, it could indicate a problem with the water pump.

Can the Water Pump Be Repaired

The water pump can be repaired but not many people are doing that. When the mechanic tells you that your water pump is bad, it is best if you replace it with a new one. A repaired water pump will never be as good as a new one. It is an important part that you really need it working 100%.

The water pump itself costs around $50 to $150. The mechanic will charge you from $300 to $500 for labor. This will depend on the location of the water pump. Many components need to be removed in order to reach the water pump.

Can a Water Pump Go Bad But Not Leak?

Yes, a water pump can go bad without leaking. While coolant leakage is one of the most common signs of a failing water pump, it’s not the only symptom. A water pump can fail in other ways.

For instance, the internal impeller that moves the coolant through the engine might wear out or break.

When this happens, the pump won’t circulate coolant properly, leading to overheating issues.

Similarly, the bearing or the seal within the water pump can fail, causing a grinding or whining noise. This can happen even without any visible coolant leak.

Another possible issue could be the deterioration of the pump’s pulley or belt. If the pulley becomes loose or the belt snaps, the water pump will stop functioning, again leading to overheating, but without any associated coolant leakage says GMB Net.

Why Is It Important To Replace Your Car Water Pump?

  • The water pump is a crucial component in the cooling system of your car, responsible for circulating coolant throughout the engine to prevent overheating.
  • A failing water pump can lead to engine overheating, which can cause severe damage and potentially result in engine failure.
  • Replacing a worn or faulty water pump can help maintain proper engine temperature and prevent overheating, ensuring optimal performance and longevity of the engine.
  • A malfunctioning water pump can lead to coolant leaks, causing coolant loss and potential engine damage if not addressed promptly.
  • Regular replacement of the water pump as per the manufacturer’s recommendations can help prevent unexpected breakdowns and costly repairs.
  • Investing in a new water pump can provide peace of mind, knowing that your engine’s cooling system is functioning properly and reducing the risk of engine damage due to overheating.
  • A properly working water pump also contributes to better fuel efficiency, as an overheating engine can negatively impact fuel consumption.
  • By replacing the water pump at the recommended intervals, you can avoid potential roadside emergencies and ensure reliable transportation.

What Should You Do When Your Water Pump Is Failing?

When your water pump is failing, it’s important to take prompt action to prevent further damage to your vehicle’s cooling system.

Here are the steps you should follow:

  1. Check for symptoms: Look out for signs of a failing water pump, such as engine overheating, coolant leaks, a non-functioning car heater, or unusual noises like growling or whining.
  2. Stop driving: If you notice any of these symptoms, it’s advisable to stop driving your vehicle immediately to avoid causing more damage to the engine.
  3. Consult a professional: Contact a qualified mechanic or automotive technician to inspect and diagnose the issue. They will be able to assess the condition of your water pump and recommend the necessary repairs or replacements.
  4. Repair or replace: Depending on the extent of the damage, the mechanic may suggest repairing the water pump or replacing it altogether. Follow their expert advice to ensure the proper functioning of your vehicle’s cooling system.
  5. Maintain your cooling system: To prevent future water pump failures, it’s essential to maintain your vehicle’s cooling system regularly. This includes checking the coolant levels, ensuring proper radiator function, and addressing any leaks or malfunctions promptly.


Q: What is a water pump?

A: A water pump is a crucial component of a car’s cooling system. It is responsible for circulating coolant throughout the engine, ensuring that it does not overheat.

Q: How can I tell if my water pump is failing?

A: There are a few indicators that your water pump may be failing. These include coolant leaks, overheating engine, whining noise from the engine, and a noticeable decrease in cooling system performance.

Q: What should I do if I have a coolant leak?

A: If you notice a coolant leak, it is essential to have your vehicle inspected by a mechanic as soon as possible. Coolant leaks can lead to engine overheating and further damage if not addressed promptly.

Q: How can I identify a coolant leak?

A: Coolant leaks can often be identified by the presence of fluid puddles beneath your vehicle, a sweet smell in the air, or a decrease in the coolant level indicated on the reservoir tank.

Q: What is the cost of water pump replacement?

A: The cost of water pump replacement can vary depending on the make and model of your vehicle, as well as the labor rates in your area. On average, expect to pay between $200 and $500 for water pump replacement.

Q: Can a bad water pump cause overheating?

A: Yes, a bad water pump can cause overheating in your engine. It is responsible for circulating coolant to dissipate heat, so if it fails, the engine may overheat.

Q: How can I tell if my water pump is making a whining noise?

A: If you hear a high-pitched, whining noise coming from the front of the engine, it may indicate a problem with the water pump. Have it inspected by a mechanic to determine the exact cause.

Q: What is the role of the water pump in the car’s cooling system?

A: The water pump plays a crucial role in the car’s cooling system by circulating coolant throughout the engine, helping to regulate its temperature and prevent overheating.

Q: What are the symptoms of a failing water pump?

A: Some common symptoms of a failing water pump include coolant leaks, overheating engine, whining noise from the engine, and a noticeable decrease in cooling system performance.

In Conclusion

These symptoms include coolant leaks, overheating, strange noises from the engine, erratic temperature gauge readings, and more.

It’s important to note that while a coolant leak is a common sign of a faulty water pump, the pump can also fail without any visible leakage.



Vide Polowenski, Senior Mechanic

The information in this article is current and up-to-date in accordance with the latest mechanic SOPs.

Please take the time to leave a comment if this article has helped you in any way, you need additional help, or you have a suggestion.

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