Replace a Broken Water Pump on a Car or Truck

A woman makes a call because of a broken down car
Don't let your ailing water pump go too long, or you may end up here. Getty

If your car or truck has a bad water pump, you're looking at a potentially very expensive repair bill. Before you hand over the debit card, consider doing the repair yourself. 

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Is it Time to Replace Your Car or Truck's Water Pump?

If your water pump is leaking slightly or making a lot of noise while the engine is running, you're probably approaching the end of its life. Do it sooner rather than later. 

Your car or truck's engine relies on the continual circulation of coolant to keep the extreme temperatures your engine creates down to a controlled minimum. All of that combustion going on inside your engine's cylinders creates a serious amount of heat, and not all of it can be carried out via the exhaust.

The most common answer was to envelope the engine in what is called a "water jacket," basically a series of passages that soak up all that hot heat and carry it away to the radiator where it will be whisked away into the air. The key element to all of this fluid circulation is the pump, called simply your water pump. This water pump uses engine power to run via a belt. Sometimes your engine stops circulating water simply because you have suffered a broken water pump belt, serpentine belt, or V-belt. If this is the case, you're lucky. It's a 30-minute fix.

If you're less lucky, your water pump has failed and you have to replace the entire unit. Before you panic, this isn't too bad a job. It will take a while, but you can save serious money by doing it yourself. Unlike some jobs, this one isn't at all tricky and doesn't require a bunch of special tools. It just takes some time. As usual, I say go for it and save that money for a rainy day.

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How to Know if Your Water Pump is Bad

There are some very obvious ways to tell if your water pump is bad, aside from simple overheating. Sometimes the pulley on the front of the water pump will just shear right off. That's a bad pump. Other times it's more subtle, but there are still signs. If everything else seems to be functioning well in your cooling system, start paying attention to your water pump. The first sign that your water pump may fail you soon is called weeping. Water pumps are designed so that when the bearings inside start to fail, the seal begins to weep, allowing small drops of coolant to leak out. This is intentional, and those drops under your car are meant to warn you that your water pump isn't going to last much longer. It's also important to listen to your water pump. You shouldn't be able to hear it. If you hear rubbing, grinding, whining or other noises coming from the area of the pump, that's a sign that the bearings inside might be failing.

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Removing Your Old Water Pump

In order to get your water pump off, you first need to access it. This means you have to remove all of the stuff that is in your way. Here we go:

  • Remove the fan shroud. This is the plastic shield surrounding the cooling fan, it is usually attached to the radiator with small bolts.
  • Drain the coolant.
  • Remove your V-Belt or water pump belt.
  • Remove the engine cooling fan.
  • Disconnect the inlet and outlet hoses to your water pump.

looking at the engine, you'll see that they are self explanatory for the most part.

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Water Pump Removal and Disconnection

After you've disconnected all of the things that get in the way of removing the old water pump you can actually unbolt the pump itself. The best way to see which bolts need to be removed on the old pump is to take a look at the new pump. This will tell you where all of the necessary bolts are located. Go ahead and remove the old water pump. Be sure to scrape away any of the old gasket that remains on the engine. This can cause a leak later.

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Installing the Replacement Water Pump

With everything cleared away and cleaned up, you are ready to install your new water pump. Before you bolt it up, it's important to check your repair manual to see if your pump requires any fittings. In the picture above you can see that the pump for this Jeep Grand Cherokee required one fitting to be installed in the new water pump before you bolt it onto the engine.

After you get the new water pump bolted on, you are ready to start putting the whole deal back together. As they say in the biz, installation is the reverse of removal, and it's always true. Be sure to scrape any old gasket off the engine before you bolt the new pump on, and now might be a good time to install a new belt rather than using the old one (inspect it for condition, at least). Don't forget to add coolant and you should be ready to go!