9 Signs of a Bad Water Pump

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Your water pump plays a crucial role to keep preventing your car from overheating. When not working properly, additional damage can happen quickly.

Unfortunately, diagnosing a bad water pump is not easy, especially if you’re not familiar with cars. 

Don’t worry. In this post, I will go over 9 signs you can look for to determine if you have a bad water pump. 

1. Whinning Noises

One of the early signs of a failing water pump is a whining or groaning noise coming from your water pump.

This sound will gradually get worse over time as the water pump weakens.

This sound is caused by the belt that drives the pulley system. When this belt becomes loose, or the pulley is not operating properly.

The most common reason is that the belt is worn out or getting loose. A malfunctioning pulley is less common but can still happen.

It’s also possible your pulley itself could be causing all the undesirable noises coming from your water pump.

Pulleys are known to rust over time, which can cause cracking between the bolt holes and unsecure the pulley from the water pump itself.

This allows the pulley to move around on the shaft, causing the pulley to flex every time the pulley spins. If you watch the water pump closely during idle, you may be able to see the pulley on the water pump wobbling back and forth.

A worn belt tensioner or a worn-out belt can cause the belt to lose on the pulley wheel, preventing the water pump impeller from spinning fast enough to circulate coolant, increasing the chances of overheating your engine properly.

Location repair shops can diagnose the difference between a lousy pulley or a bad water pump in this situation.

2. Leaking Coolant

Another common sign of your water pump failing is coolant leaking from the water pump. The leaking coolant typically pool’s under the pump.

Water pumps are usually located toward the front of the engine. This is because the water pump uses the same pulley and belt system that the alternator uses.

When inspecting for a leaking water pump, you want to look under your car for coolant. Coolant can have a green or orangish color depending on the type of coolant.

If you can’t identify the coolant under your engine, you can check your coolant level. The coolant tank is located under the hood in a transparent tank near the radiator. This location can vary depending on the type of car you have.

If your coolant tank is below or near the minimum line on your coolant tank, this is a sign that you might have a leak in your water pump.

You can refill your tank and then monitor how fast the coolant level changes. In most cases, coolant refills are not don’t often. You might have to wait for between 10,000 and 30,000 miles to see a significant change in coolant level.

The most common places a water pump will leak from are the shaft seal and the water pump gasket.

Once your water pump bearings start wearing out, your water pump shaft will begin to wobble. If your water pump shaft starts to wobble, coolant will start leaking out of the shaft seal.

Water pump gaskets typically fail due to old age or damage due to debris. It will start to leak around the water pump bolts.

In this case, you are better off replacing the water pump completely. Only fixing the leak could cause lead to further damage or leaks in the future.

4. Overheating Engine

An overheating engine is another sign that you have a bad water pump. Your combustion engine relies on your radiator, radiator fan, radiator hoses, water pump, and coolant. If any of the following are not working properly, your engine can overheat. 

When your water pump fails to circulate coolant through your engine, your engine is more likely to overheat. 

An overheating engine can lead to a variety of issues depending on if not addressed. Some of the issues that overheating can cause includes: 

  • Warping metal 
  • Swelling metal 
  • Head Gasket damage 
  • Coolant engine leakage 
  • Crack engine head 
  • Cracked cylinder heads 
  • Burned pistons
  • Engine failure

If you ever experience your vehicle’s temperature gauge increasing quickly or beyond the halfway point, pull over immediately. Locate a safe area and turn your car off to prevent damaging your engine. Call your local towing company to have the vehicle towed to a repair shop. 

5. Steam Coming from your Radiator

If you see a puff of smoke or steam coming from your engine bay area, your engine is overheating. The steam coming is coolant boiling inside your radiator. This boiling causes tremendous pressure forcing steam to leak past your radiator cap.

Never try to open your radiator cap when hot. Pull your vehicle over, turn off your ignition, and let your car rest for 20 minutes.

If this does happen, you should inspect your water pump for any issues. If you don’t suspect any damage, leaks, or low coolant levels, you might want to take your car to a mechanic.

A mechanic will determine what issues caused the steam from your radiator and if a bad water pump caused it.

6. Deposit Buildup, Rust and Water Pump Corrosion

Another sign of a bad water pump is if there is visible damage on your water pump. This includes deposite buildup, rust, and corrosion.

Rust will damage the inside of your water pump. This damage can cause coolant to leak through our water pump.

When deposits build up inside your water pump, this can jam the propellers of your water pump. This will stop the coolant from pumping through your engine.

In some cases, a leak can also cause orange, reddish, or pinkish deposits to build-up on the outside of your water pump.

If you see any of the following around your water pump. It would be smart to go ahead and replace your water pump before the pump gets worse over time.

7. Excess Coolant Leaking From The Weep Hole

Water pumps have a weep hole on the dry side of the water pump. This hole is designed to release excess pressure from the water pump.

If your water pump begins leaking coolant from the weep hole, this is a sign there is an issue. In some cases, minor leakage is normal from the weep hole, but excessive leakage is a cause for concern.

8. Low Coolant Reading

Leaks are not always large. In some cases, leaks are small and can slowly drain your coolant over time.
If you see that your coolant has below the halfway point or near the minimum, this can be a sign that you have a bad water pump.

Coolant doesn’t typically change levels very fast. If there is some change in the coolant level, then you should inspect your water pump thoroughly.

You typically don’t need to change or refill your coolant. It’s more common than you need to flush out your coolant and replenish it with fresh coolant.

You can check your coolant levels on the opaque tank under your hood. The tank is typically near the radiator.

The first sign of low coolant levels will be your temperature gauge will start displaying higher than normal engine temperatures under the same driving conditions. Over time the temperature gauge will read higher and higher engine temperatures until the engine overheats.

To prevent this from happening to your vehicle. Pop the hood and check your coolant level while the engine is cool using an antifreeze tester.

Using an antifreeze tester will enable you to measure your coolant lows accurately. The tool allows users to visually inspect rust and sediment by testing the coolant with an antifreeze tester.

9. Faulty Temperature Gauge

A faulty temperature gauge is another sign that you have a bad water pump. A defective gauge will fluctuate or flicker up and down.

This is a sign that your water pump is malfunctioning. When you first start your vehicle, the temperature gauge should be reading a low engine temperature. 

As the car warms up, the temperature gauge needle should start to rise until the vehicle engine reaches normal operating temperature.

Your stock temperature gauge typically has a mark around the halfway point indicating the desired engine temperature. The higher your temperature gets, some vehicles’ temperature gauge will turn red to help inform the driver the car is running too hot.

Normally your vehicle engine temperature gauge should be steady. A temperature gauge that fluctuates dramatically from cool to heat and vice versa in a short period. This is an indication you need to replace your existing temperature gauge to get a correct reading.

Frequently Asked Questions (FAQ)

What Does a Failing Water Pump Look Like?

It’s hard to identify a failing water pump, but the most important visual signs are gunk, deposits, and dried coolant on the side of the tank.

The water pump has dried old coolant and gunk around the leaking areas, typically around the water pump gasket areas. A failing water pump could have a wet appearance around the water pump gasket due to an active leak.

The pulley shaft going into the water pump can look wobbly as the bearing starts to wear over time. The water pump will screeching noises as the impeller inside the water pump worsens.

Another sign of a failing water pump is leakage. Coolant leaking and puddling on the ground is one of the most common issues caused by water pumps.

Can You Drive A Car With A Bad Water Pump?

Yes, you can drive on a bad water pump for a short time.

If you suspect issues with your water pump you should at least get your car looked at by a professional.

This will help you determine the severity of the issue before you can continue driving.

For example, if your water pump stops working altogether, the excess heat can destroy your damage.

Driving on a bad water pump can turn a simple fix into thousands of dollars worth of damage.

How much does it cost to replace a water pump?

Typically water pump replacement prices range between $400-$650 depending on your parts and labor. A brand new water pump will cost you between $200-$300, depending on the brand and type of water pump.

You can expect to pay between $50 and $150 per hour for a mechanic for labor. Replacing a water pump can take anywhere between two and three hours. This means you can expect to pay between $150 and $450 for labor.

To save money, you could replace the water pump yourself, depending on your skillset. I wouldn’t recommend changing out your water pump if you are not mechanically inclined.

Can a water pump be bad without leaking?

Yes, rust and corrosion around the water pump gasket seals is a sign your water pump is going bad. Once holes form on your water pump from rust and corrosion, coolant will start leaking soon out of the rusted areas.

Will a bad water pump rattle

Yes, water pumps can start to rattle when they get bad. 

Two of the main reasons a water pump will start to rattle are 

  1. The bearings and bolts on the water pump are damaged or worn out. 
  2. The pulley system on your water pump is not operating correctly. 


How long does it take to replace a water pump?

Mechanics typically take between two and three hours to replace a bad water pump. Depending on the position of the water pump, this can take longer or shorter. 

For example, some water pumps are positions under the car while others can be accessed from the hood. Those that can be accessed from the hood are faster to replace than other water pumps. 

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