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How to Install a Water Pump on a Car

Dan Ferrell writes about DIY car maintenance and repair. He has certifications in Automation and Control Technology and Technical Writing.

On some models, you can find the water pump next to the timing belt.

On some models, you can find the water pump next to the timing belt.

Knowing how to install a water pump can save you on average about $500—much more on some particular car models.

However, replacing a water pump requires more than wanting to save some money. You need to know the correct procedure, and whether you have to replace other components as well (even if they show no signs of problems). Otherwise, your repair may turn out to be more expensive than you would've paid a shop to do the job in the first place.

Whether your water pump is leaking coolant, barely circulating coolant (or not at all), howling whenever the engine is running, or simply has reached its service schedule (usually between 50,000 and 100,000 miles), you need to replace it. And the sooner, the better.

Replacing a water pump requires careful attention to detail, and you can do this with planning and organization.

Your grade of difficulty will vary depending on your particular vehicle make and model (how many parts you have to remove to gain access to the pump), your personal car-repair experience (do you usually change the thermostat, engine oil, alternator, belts, or brake pads?). Whatever your level of expertise, it's a good idea to have the repair manual for your vehicle at hand, especially if you need to remove more than one part to reach your water pump. You can find an inexpensive copy at most auto parts stores or online.

Whatever your particular situation, this guide will help you to replace the pump in your vehicle.

NOTE: This guide doesn't apply to electric water pumps.


I. How to Remove the Water Pump

Do I Really Need to Replace the Timing Belt at the Same Time?

II. Preparing to Install the New Pump

Tricks to Make Your New Water Pump Seal Correctly

III. How to Install Your Water Pump

Top 5 Tips to Increase Water Pump Service Life

Drain coolant before you start replacing the water pump

Drain coolant before you start replacing the water pump

I. How to Remove the Water Pump

Before you start, check in advance where your water pump is located, how many parts you may have to remove (belts, power steering pump, alternator, ac compressor, mounting brackets, radiator fan), and gather the tools you may need for the project. Also, have the new pump on hand, if possible; it may help you to locate all the bolts you need to remove on the old one and make sure you have the correct replacement.

1. Park your car on a flat surface and with plenty of room to move around the front of your vehicle.

2. Wait for the engine to cool if necessary.

3. If you need to work close to the electric fan wiring (or some other electrical components), disconnect the negative (black) battery cable and secure it away from the battery.

4. Place a drain pan under the radiator and open the drain valve or disconnect the lower radiator hose. If you plan on reusing the drained coolant (although you may want to replace it now if it's more than one year old), clean the pan and put it away in a safe place.

5. Start removing those components that will give you access to the water pump. If the radiator fan mounts on the water pump, mark the side facing the radiator before removing it for proper replacement. On some vehicle models, you'll need a special tool (that you may loan from your local auto parts store) to remove the radiator fan. Also, on a few of these models, you may have to remove the radiator for clearance as well.

6. Before removing any belts (timing belt, drive belt or serpentine belt), note how it weaves around the different pulleys so that you reinstall it correctly. And take note of the following recommendations:

  • If you are removing a drive belt or serpentine belt that runs the water pump, loosen the water pump pulley bolts first, if any. It makes it easier to remove the pulley afterwards. To loosen the bolts, lodge a large screwdriver between two of the pulley bolts and start loosening the other bolt(s).
  • Also, on some models, if you need to remove the timing belt, you may have to remove the belt tensioner and idler pulley(s) for replacement. Check your repair manual, if necessary, for the proper procedure. You'll need to preserve engine timing.

7. As you remove items, place them on a workbench or similar working surface in the same order you are removing them. That way, when the time comes to reinstall them, you just follow the sequence in reverse. It really speeds up your work.

8. Once you gain access to your water pump, loosen the hose clamp at the water pump using a screwdriver, or set of pliers if it has a spring clamp type (on some models, a heater hose also connects to the water pump).

9. Then, disconnect the hose from the water pump fitting. You may need to break the hose seal at the pump. For this, wrap a shop rag around the end of the hose and use a pair of rib joint pliers to twist the hose.

10. Now, gradually start unscrewing the bolts holding your water pump in place. How to handle the bolts:

  • Keep all the bolts organized. The pump mounting bolts may come in different lengths, and some applications also use studs in place of bolts.
  • Keep notes of the location of each bolt so that you install them in their proper place; otherwise, you may end up with a coolant leak after installing your new water pump. On some applications, you may need to remove up to 12 bolts or more. If you have the new water pump with you, take a look at it to check how many bolts you'll need to remove.

11. After removing all the mounting bolts, carefully try to detach the pump from the engine block. If the pump seems stuck, do the following:

  • Gently tap the pump with a rubber mallet or a block of wood and a hammer. Do not pry the pump off the engine or you may damage the mounting surface and cause the new pump to leak.
  • If this doesn't work, double check and make sure you've removed all the mounting bolts. Check your new pump for the number of mounting bolt holes. It's easy to overlook hidden bolts. Or check your car repair manual.
Replace the timing belt if you need to remove it to access the water pump or when it gets contaminated with coolant.

Replace the timing belt if you need to remove it to access the water pump or when it gets contaminated with coolant.

Do I Really Need to Replace the Timing Belt at the Same Time?

1. If you need to remove the timing belt to replace the water pump, consider replacing the belt, tensioner and idler pulleys at the same time, if it is more than two years old. A timing belt lasts about as long as the water pump.

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  • This is a little preventive maintenance measure. Think towing charges, engine damage and time lost if the timing belt breaks on the road. This is why replacing both items at the same time is standard procedure in most car repair shops.
  • Follow the instructions in your repair manual to keep engine timing correct, or you risk damage to the engine.

2. Some car models use a pressed-on pulley on the water pump that probably you'll need to reuse. Do not try to hammer off the pulley on these type of pumps. Just take it to a shop and have them transfer the pulley to the new pump. You'll save yourself money, time and headaches.

On some vehicles, you need to remove the radiator fan to replace the water pump.

On some vehicles, you need to remove the radiator fan to replace the water pump.

II. Preparing to Install the New Pump

1. Now, scrape off all traces of old gasket material from the engine mounting surface
Work the mounting surface using a plastic or gasket scraper, to prevent scratching the surface and the new pump to leak.

2. Remove sediment and scale from the pump cavity on the engine block.

3. Clean the mounting surface with a clean shop rag and lacquer thinner or acetone.

4. Clean the bolt threads and mounting holes on the engine block to remove old sealant, if necessary. For this, you can use a tap and die set.

With the surface perfectly clean, try the new pump onto the engine mounting surface. Make sure you can fit the pump straight into place to keep the new seal from moving around.

A leaking water pump will leave wet marks under your vehicle.

A leaking water pump will leave wet marks under your vehicle.

Tricks to Make Your New Water Pump Seal Correctly

When installing a new water pump, you'll need to install a new gasket, special gasket maker (RTV and anaerobic types are the most common), or an O-ring seal, depending on your application (if necessary, check your repair manual). Follow the next strategies with each for proper installation:

Installing a new Gasket:

1. Evenly apply a light coat of the adhesive recommended by the pump manufacturer (or repair manual) to the mating surface of your new water pump.

2. Align and sit the new gasket onto the water pump surface.

3. Then apply an even light coat of adhesive to the gasket surface facing the engine.

4. Slip two or three mounting bolts on the water pump to align your new pump onto the mounting surface of the engine block. This will prevent sliding the pump on the engine surface to align the bolt holes and smearing the adhesive.

Installing a Chemical Gasket:

1. If you're using a chemical gasket (form-in-place gasket), use an approved sealer as recommended by your water pump manufacturer or consult your repair manual.

2. Apply the gasket in a continuous bead of about 1/8 inches (3 mm) around the surface to seal.

3. Place sealer around bolt holes to form a good seal.

4. Once you applied the sealer, slip two or three mounting bolts on the water pump and use them to align your new pump onto the mounting surface of the engine block.

This will make it easier to fit the new pump straight onto the mounting surface and will prevent smearing the seal.

Installing an O-ring Seal:

1. Apply a light coat of sealant or moly-based grease to the water pump groove to hold the new O-ring in place.

2. Fit the new O-ring carefully into its groove.

3. Make sure the O-ring fills the furrow cut completely to prevent leaks.

III. How to Install Your Water Pump

Once you have the new water pump in place onto the engine mounting surface:

1. Position the new pump straight onto the mounting surface of the engine block. Make sure the bolt holes align correctly.

2. Then, apply a dab of RTV sealant to the bolts and install the bolts finger tight to hold your new water pump in place.

3. Double check that all the bolts are in place and in their original location.

4. Gradually start tightening the bolts following a crisscross pattern.

5. Torque the bolts to specification according to your repair manual. This will create a better seal without damaging the gasket or new pump.

6. Once you've finished installing the water pump, reinstall the accessories, brackets or belts you had to remove to access the pump.

7. Connect the radiator hose to the water pump.

8. Wait for the sealer on the water pump to cure, if necessary, according to the sealer manufacturer instructions.

9. Refill the cooling system. If possible, use new coolant. Check your car owner's manual or repair manual for the recommended antifreeze for your particular vehicle make and model.

10. Connect the negative cable to the battery.

11. Start the engine and allow it to reach operating temperature.

12. Check for leaks. Note: keep in mind that the weep hole of your new water pump might seep some coolant while the new pump seal self-adjusts to operating conditions.

Top 5 Tips to Increase Water Pump Service Life

Often, car water pumps fail prematurely because of lack of proper engine maintenance. Follow the next five recommendations to increase the service life of your new pump.

1. Change coolant at the recommended service interval. Old, worn out coolant allows rust and scale to build up around the pump impeller causing it to deteriorate and fail along with other system components.

2. Install a new belt with the appropriate tension at the recommended car manufacturer (see your repair manual or car owner's manual). Also, make sure the belt aligns with all the pulleys it has to run. An improperly installed belt may damage your new water pump.

3. Diagnose and repair any overheating engine problems as soon as possible. Overheating will reduce your new water pump service life considerably.

4. Replace your old water pump with an OEM quality part or better for good cooling system operation.

5. If the timing belt runs your old water pump, also replace the timing belt, idler and tensioner, if it is two or more years old; also, if you are replacing the water pump because it was leaking, replace the timing belt even if it's been in service less than a year. You'll save time and money in car service expenses and, possibly, middle of the road breakdowns—and engine damage on some engine applications.

The hardest part of replacing your water pump is making sure you won't end up with a coolant leak. But you can accomplish this by giving yourself plenty of time to complete the project without rushing. Get organized and pay attention to details during the process. Even if replacing the pump in your vehicle seems relatively easy, keep your repair manual at hand so that you have the proper information about your repair when the need arises.

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

© 2016 Dan Ferrell

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