I write about maintaining and troubleshooting cars and other motor vehicles!
Does Your Water Pump Need Replacing?
If any of the following apply to your vehicle, it may be time to replace the water pump:
- Has your car overheated lately?
- Do you find yourself "topping off" the radiator reservoir more often?
- Is there a puddle of radiator fluid under your car?
- Can you move the water pump pulley back and forth at all?
- Does your car have over 50,000 miles on it?
Water pumps wear out eventually, just like any moving part. The water pump is a critical part of your engine. The coolant is like the blood flowing through your engine's veins. If the fluid leaks out....it dies.
The water pump is usually located front and center of the engine. It sits against the engine behind a pulley and the fan. There are "weep" holes located on the bottom and the top of the pump. These weep holes start to leak when the pump is wearing out. If the pump is not replaced, eventually the bearings will wear out, and the car will overheat, which could cause major engine damage.
To my lady friends out there, who many know, I say that when the car overheats it means that your engine has become so hot the metal is breaking down; in other words, your engine is literally melting! You must stop the car and allow it to cool down or risk blowing your engine.
These are all signs of a water pump in need of replacement.
So, let's pull off those acrylic nails, pull our hair back, and get started.
Where Is the Water Pump?
Below is a nice diagram of the location of the water pump on a standard V8 engine. On engine types referred to as "sideways," the water pump is located on the side.
Let's Head to the Auto Shop
The replacement of a water pump can take from 1.5 hours to 3 hours depending on your experience level. Experience matters only because several items must be removed to access the water pump. Simple items, but time-consuming to remove. If you're experienced than you're going to know exactly what needs to be removed and start pulling parts off left and right. If you're not experienced you're going to be looking about, reading your shop manual and being more cautious. Being cautious is good, just make sure you allot yourself enough time to complete this endeavor.
Let's head over to the nearest auto shop for a new pump. They run $50 - $80 for a normal, run-of-the-mill water pump. If you enjoy spending money, I'm certain you can find a chrome-plated one for several hundred, but for this article we'll go with run-of-the-mill.
Be sure to have the make, model and year of your car with you when you head for the auto shop. Engine size and type is always a help too. Water pumps can vary depending on the size of your engine.
If you decide to use sealant or if the instructions in the box recommend sealant, by all means pick some up while you're there. The sealant should say right on the tube if it is good for high temperatures and will withstand constant water contact. These things are important because some sealant can't handle high heat or water and they will break down over time and that's NOT going to be good after all your work!
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Tools for the Job
Now that you have your new water pump, it's time to collect the tools we'll need to complete the job.
- 10mm and 14mm wrenches and sockets
- tube of sealant (optional, I prefer it myself)
- a breaker bar or strong, long wrench to move the tensioner
- 5/8" socket for the tensioner
- new water pump
- radiator fluid
- catch basin for fluid
- torque wrench (the mounting bolts need to be torqued down)
And that's it! Replacing the water pump doesn't require a lot of tools because many of the nuts and bolts require the same size.
Why You Need a Torque Wrench
Don't skip the torque wrench. It's a vital tool in this application. When the mechanic puts the torque wrench on a nut or bolt, and twists the nut or bolt in a tightening fashion, the torque wrench indicates how tight that nut or bolt is. Your particular vehicle's specifications will tell you what "poundage" or "inch-pounds" you need to set on your nut or bolt. You do this by watching the needle on the torque wrench until it reaches the specified poundage, or inch-pounds. When the needle is pointing to the number you want, you should be able to hold the torque wrench at that spot and the nut or bolt won't twist anymore. On some torque wrenches which have a clutch inside you set the dial on it to what number you need and it automatically stops turning when you have tightened to that number. Torque wrenches are surprisingly expensive. Before dumping a bunch of money buying one, check out your local O'Reilly's. They rent out all kinds of tools. They may have a torque wrench to rent! If you return it, and it's in the same condition as when you took it, they give you your money back :)! You can't beat that!
Now back to why you need a torque wrench: if the bolts are not tightened evenly, or if the rotating of the engine shakes the bolts loose, a weak bolt will begin to allow water to seep through. The seeping water may even blow out your pump gasket. That would suck, so let's make sure we have a torque wrench handy.
Still Shot Instructional Video: Replacing the Water Pump on a 1989 Silverado
The video below is a "Still Shot Instructional Video" of a water pump replacement. The vehicle in the video is a 1989 (year), Chevrolet (make), Silverado 3500 (model), with a 454 (engine size).
Below the video are step-by-step instructions, basically the same information as the video but with a little more detail.
Removing the Water Pump
1. Disconnect the negative battery cable at the battery. This will prevent an accidental electric shock.
2. Now drain the radiator fluid by opening the radiator cap and unscrewing the draincock. The radiator cap is located on top of the radiator and the draincock is normally located on the opposite side of the radiator cap but on the bottom of the radiator. It will be facing toward the rear of the vehicle. You reach your hand down and unscrew the valve. It can be firm to twist. You may need to wedge a pair of pliers down there to help get the valve started.
Caution: Radiator Fluid
Radiator fluid is highly toxic to pets; even the smallest amount can poison your pet. Collect radiator fluid in a container and disposed of properly. There are collection centers listed in the phonebook where you can drop off your radiator fluid.
3. Remove the fan shroud. This is located at the front of the engine compartment. It's a piece of plastic that encircles the fan and attaches to the body of the vehicle. There are two to three screws (usually 10 millimeter) along the top of the shroud and four more halfway down the shroud. To find these screws halfway down, locate the end of the shroud and run your hand down the edge until you can feel a lip. These 10 mm screws go through that lip into the lower part of the fan shroud holding them together. These screws are also 10 mm.
4. Now it's time to remove the serpentine belt, the long belt that winds through all those pulleys to keep everything running and in sync. Check the front edge of the engine compartment for the diagram showing how your belt should be routed. If it's not there, or unreadable, pull out your shop manual and look it up. Compare the picture in the shop manual to the actual routing of your belt to be sure you're looking at the correct set-up, then mark the one that is exactly the same. If you re-route this belt incorrectly, it can destroy the components it runs; if you miss a pulley, it can destroy your engine. Personally, I take a pen to paper and draw my own rough (very rough, lol) diagram of the pulleys and route of the belt. Then I know for sure I have the correct route set up. It may be helpful to view the video at this point because it demonstrates how to move the tensioner so you can pull the belt off. You place a socket on the tensioner, attach a breaker bar or similar leveraging bar, and turn the spring-loaded tensioner until there is enough slack that the belt will come off the pulleys. Then, gently release the tensioner back to its position.
5. The nuts on the fan come off now. Wedge a long wrench or a board between the fan and other nuts to hold the fan in place while you loosen each nut. Once they are loose you don't need the wedge any longer. Unscrew them the rest of the way by hand and set them somewhere safe, where they won't get lost. Pull the fan out and do the same thing with it. You don't want any of the blades bent. The pulley comes right off after the fan.
6. Now you should be at the water pump. The bolts can be difficult to see because of their location. There are four of them, two on each side, and they are over-under style (one above the other). A ratchet with an extension is your best choice here because the socket needs to go about five inches in to reach the bolts.
7. Once the bolts are removed, you may need to tap on the old water pump to get it free from the engine. Once it's separated from the engine, carefully lift it out so you don't damage your radiator with its front wheel, and pull it out of the engine.
Install the New Water Pump
The mating surface (the point where the water pump meets the engine) must have all old gasket material, grease and grime removed. This is one of those things you really want to make sure you do well or the job will pointless. So let's do it right the first time!
- First, remove the four fan bolts from the old water pump and put them on the new water pump.
- The new water pump should have a new plug supplied with it; put this plug in the same spot it is on the old pump. If a new plug is not provided (unlikely, but can happen), remove the old plug, which can prove to be very difficult. Soak the old plug with "Screw Loose" or WD-40 to loosen it up. You may even need to smack the heck out of the old pump to break that old plug loose. Yep, you may look like a raving lunatic smacking the old pump with a hammer, but just mention what you're doing and anyone that knows engines will understand! Now that you got that plug out of the old water pump, put it in the same spot on the new pump.
- Any other adapters on the old pump you should transfer to the new water pump.
- Using emery cloth, fine sandpaper (220 or higher), or a Dremel (use with caution, no gouging), clean the mating surface.
- When the mating surface is clean and dry, prepare the new water pump for installation. It can be tricky mounting the pump while keeping the gaskets aligned and starting the bolts. The pump can be rather heavy, in an award position, with the gaskets slipping here and there. I have had a couple of failed installs because gaskets slipped, causing water to gush out and leaving me with a water pump to re-install, but not anymore. You should do whatever works for you, but this is how I do it now. Apply a thin line of gasket sealant to the pump mating surface. Set your gaskets on the sealant making sure to line up the holes in the gasket with the holes on the water pump. Apply another thin line of gasket sealant on the gaskets. Carefully slide the bolts through the holes and gasket and put some gasket sealant on the end of the bolt with the threads. Now you're ready to mount the water pump.
- With bolts in place, carefully lower the new water pump into position (if you have a helper, this would be a nice time for them to help), and start the bolts, by hand, into their respective holes being sure that the gaskets stay in place. Once you have them started in a few turns, then you can put a socket to them.
- Once the bolts are snug but not tight, take out your torque wrench. Look up the torque specification in your shop manual (it should be somewhere between 20 foot-lbs and 30 foot-lbs) and torque all four bolts.
- Connect the water pump hoses. This is a good time to replace any hoses showing signs of wear. Tighten the hose clamps.
- Set the pulley on the water pump wheel.
- Set the fan on the water pump wheel.
- Put the nuts back on to the bolts sticking through the fan holes. Snug them down using a leverage bar again.
- Referring to your chosen serpentine belt diagram, re-route your serpentine belt, then twist the tensioner to put the final length of belt on.
- Replace the fan shroud.
- Close the draincock.
- Re-connect the battery negative cable.
- Fill the radiator with radiator fluid. Burp the hoses by squeezing the large upper hose several times.
- While the radiator cap is still off, start the engine. Turn the heater on to high heat. Since the radiator is the source of heat for the inside of your vehicle, you want to flow heat through that system as well as through the engine. As the new pump starts working it will fill the system that was drained and you'll need to add coolant. Add coolant as needed until it stays full. Then replace the radiator cap.
- Get down and look for any leaks while it's still running. Check the temperature gauge. It should remain at or below 210° after the engine is warmed up (about 10 minutes at idle).
If you see ANY leaking, tear down the job and do it again. Any leaks WILL get worse and you have pride in your work so go back and do it again. 99% of the time, the cause of the leak is either that the silly gaskets at the mounting surface have moved or the torque is incorrect.
If there's not a leak in sight, congratulations!! YOU DID IT!! You're good to go for another 50,000 miles or more!
Thank you for reading,
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.