Bad water pump [Expert advice to diagnose & fix]

Think you may have a bad water pump? Watch this video for expert diagnostic tips, and to learn about symptoms, causes, and how to fix them. 

How to Diagnose a Bad Water Pump 

What are the typical symptoms? 

  • Your car may feel like it’s overheating as well as running hotter than usual. 
  • Leaking coolant: You could actually smell this before you find the leak itself. Coolant has a sweet smell, and some people compare it to the smell of maple syrup. 
  • Finally, Pooling, puddling, and/or dried coolant, depending on how long the water pump has been leaking for. 

Bad Water Pump Common Questions

Can you drive with it?

No, while the vehicle will run and drive with a bad water pump, you still should not drive the vehicle. It means the vehicle is not cooling properly and can result in overheating of the engine and possibly causing damage to other parts of the engine.

What sound does it make?

When it has a bad bearing you will hear a whining, squeaking or grinding noise coming from the front of your engine. Not all failed water pumps will make noise though, some leak silently.

Can it cause no heat?

Yes, a bad water pump can cause no heat. This is because the water pump is what circulates the coolant through the engine and heater core. If it has failed, it is unable to pump the coolant properly, resulting in little to no coolant circulating through the vehicles heater core causing no heat.

Can it fail without leaking?

Yes, when a bearing for the pulley starts to fail they will make a whining, squeaking, or grinding noise before the water pump will start to leak. If the seal is what failed or the bearing completely failed, you will notice coolant leaking out.

What causes it to go bad or fail? 

The most common cause is worn or damaged water pump seals that cause coolant to leak, or “weep,” out of the pump weep holes. 

Bad Water Pump
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How do I diagnose and fix a bad water pump? 

Check for coolant leaks

Bad Water Pump
What Fluid is Leaking
Click here to see what fluid is leaking from your car.
  • Check the engine temperature gauge to see if the engine is running hot
  • Check for a sweet smell, similar to maple syrup
  • Look under the vehicle for fluid the color of your coolant
  • Soak up leaks with a paper towel to check the color

Diagnosing a Coolant Leak

  • After the car has run, listen to hear if the cooling fans are running
  • If the fan is not running, that may be the cause of the overheating condition
  • Allow the engine to cool down
  • Check the coolant reservoir level
  • Twist off the radiator cap
  • Check the radiator coolant level
  • Low coolant indicates a leak
  • Visually inspect the upper radiator hose for leaks
  • Check where the upper radiator hose connects to the engine
  • Visually inspect the lower radiator hose for leaks
  • Check where the lower radiator hose connects to the engine
  • Inspect the heater core hoses by the firewall for leaks
  • Check where the heater core hoses connect to the engine for leaks
  • Look into the engine compartment from underneath for leaks
  • Trace any leaks back to their source

When water pumps show obvious signs of leaking, and for a long period of time, they need to be replaced. 

How to replace a bad water pump

For more how-to videos related to your year, make and model click here.

Maintenance

Although water pumps aren’t considered normal wear parts, in vehicles where they’re driven by the timing belt, they can be difficult to replace if they fail. That’s why it’s common to replace them before they could fail, and our mechanic recommends replacing them during regular timing belt maintenance. 

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