The first step in replacing a water pump is draining the coolant
Every combustion engine is equipped with a water pump or coolant pump as some call it. This pump is used to
circulate coolant within the cooling system to help keep the engine at running
temperature during it's normal operation. A
water pump is bolted to the front of
the engine block or timing chain cover and can be driven by the serpentine belt, timing belt or timing
chain. When replacing a water pump that is driven by a timing belt or chain it
best to replace the timing belt or chain with a new unit since it will be take
off anyway. This will require a diagram
which will show you where the timing marks are so you can reassemble the engine
What Goes Wrong?
When a water pump goes
bad it can do so in three different ways. The first is the shaft seal which will
coolant to leak from the pump's weep hole or sealing gasket which is located
between the pump housing and the engine block which will cause
the engine to overheat. The second failure is the shaft bearing will fail
causing a grinding, rumble or squeaking noise. The last way a water pump can go
bad is if the impeller either falls off or deteriorates failing to circulate the
coolant throughout the engine and radiator.
How Long Do They Last?
A water pump endures the rotation speed of the engine and tension against its bearings
from the serpentine belt. In time this will wear the water pump out and cause a
failure. The main safe seal is subject to coolant system
pressure and the heat of the engine which can wear the seal out causing a leak. A
water pump will typical last between 80,000 (128747 km) and 120,000 miles
(193121 km) in most cases.
How Much Does it Cost?
The replacement cost of a water pump will vary due to the amount of labor it
will take to get to the pump in a particular application. The determining
factory is: front or rear wheel drive, (front wheel drive car's are generally
tougher due to the limited space to work on the engine) and if the water pump is
timing belt or timing chain driven. These jobs can take longer because more if
the engine must be taken apart to replace the pump.
If a repair garage or the car dealer is doing the job you can expect to pay
between $350.00 and $650.00 (US). If you are doing the job yourself you will
need a new water pump which will
cost between $65.00 and $130.00 on Amazon or the local parts store. You will
also need additional coolant and
to rent or buy a water pump pulley holder tool which is also at Amazon for about
$20.00 (US). We will show you how to get around the tool is this guide.
There is a video of this job being done at the bottom of this guide.
Let's Get Started
In most cases you will need to
raise the car up
using a floor jack and supporting it with jack stands. Its also a good idea
to use latex gloves and protective eyewear. Start with the engine cool and the
car on level ground. In the guide below the job is being performed on a rear wheel drive car.
On front wheel drive car models some of the following steps may not apply. Use a
small container to store the screws and bolts so they do not get lost. Also
clear a place for the parts that will be removed while the repair is being done.
1. Loosen Radiator Cap
Locate and slowly loosen the radiator or reservoir cap to relieve any
residual pressure inside the cooling system. This will also allow the system to
drain more rapidly.
2. Drain Coolant
The water pump is submerged in engine coolant so the system must be drained
down to avoid spillage when unbolting the pump from the
or timing cover. Open the radiator drain valve or remove the lower radiator hose while using a
fluid catch basin to
drain the coolant into.
3. Disconnect Battery
Anytime you are working on the engine it is a good idea to
battery to ensure there are no accidental electrical short circuits by
contacting power to ground with a wrench or ratchet. You may want to record the radio
presets before this step because they will need to be re-entered once the
battery is reconnected.
4. Remove Upper Radiator Hose
To help gain access to the water pump a few parts will needed to be removed
first. On this car we will start by
removing the upper radiator hose
first. Also remove any plastic clips or covers to help uncover the engine. Here we are using a hose
clamp tool but you can also use a pair of channel locks to do the job.
5. Remove Upper Fan Shroud
Remove the mounting bolts that hold the upper radiator shroud to the radiator
and to the lower part of the shroud. In some cases the fan shroud is all one
piece which you will be able to remove once the fan blade and clutch is removed.
6. Remove Cooling Fan
The cooling fan may or may not be connected to the water pump. Some cars use
an electric fan which will be attached to the radiator fan shroud and will come
out all in one piece. In this example the fan is mounted to the water pump. You
will need to use a pulley holding tool or as we have done use a large pipe
wrench. This is to keep the pulley from turning while loosening the clutch fan nut.
Use either a
large wrench or the proper tool to remove the fan clutch from the water
7. Remove the Serpentine Belt
Locate the serpentine belt tensioner and while using a ratchet or wrench
apply pressure to release the belt from the pulleys. If you cannot find a
diagram of the belt's routing use your cell phone a take a picture of the belt
and the pulleys so you can install the belt back on when putting the job back
together. When replacing the water pump it is a good idea the
serpentine belt since it will be off already.
8. Remove the Water Pump Pulley
The water pump pulley must be held in place to break loose the mounting bolts.
This can be done by using a large standard (flat blade) screwdriver and wedging
it in between the bolts and the center thread. Then use a socket or wrench to loosen
and remove the bolts. Once the bolts have been removed lift the pulley from the
water pump. On Some water pumps like a GM V6 or V8 the pulley in stay on the water
pump and cannot be removed.
9. Remove the Water pump
This will expose the water pump and the mounting bolts. There may be
additional hoses, brackets and covers that need to be removed depending on design which you
will need to look at and decide if they need to be taken off or not before the
pump can be removed.
Locate the bolts that hold the water pump to the engine block or timing
cover. Use a socket or wrench the remove the bolts counterclockwise. Take note
on which bolts come out of which location because some bolts can be different
lengths which can create problem during reassembly.
Once all of the mounting bolts have been removed shock the pump to break the
seal which will enable the pump to be removed from it's location. Using a small
hammer gently tap the pump housing or fan mounting flange to help break the
seal. A small amount of coolant will also be released so have your fluid catch
Grasp the water pump and wiggle it loose and be careful no to drop it because
it could roll into the radiator and cause a leak taking the fun out of the job.
10. Match the New Water Pump
Remove the new water pump from the box and match it to the old pump. Check
the mounting flange for the fan clutch and the gasket surface they
should match identically. Also, a new gasket or O ring will be included with the
new water pump. This will help seal the pump to the block or timing cover and avoid leaks.
Install the new gasket or O ring seal while making sure not to damage the
integrity of either the gasket or the seal. This step is important because if
you cause a leak you will be doing the job over again.
11. Install New Water Pump
Now that the new water pump is ready to be installed you must prepare the
engine block or timing cover. This means cleaning the sealing surface for the
new O ring seal or gasket to mate against. Use a shop towel and wipe away any
dirt and grease from the area. If the water pump uses a gasket use a gasket
scraper to remove the old gasket until the metal is clean and smooth. Then use a
small amount of gasket sealer (silicone rubber) while mounting the gasket to the
pump. This part is as equally important as preparing the water pump for installation.
Lower the new water pump down into the engine bay and gently insert it into
the engine block or timing cover and push it into place. Insert one of the
pump's mounting bolts to help keep the unit in place and tighten it by hand, follow up with the remaining bolts. Be sure to insert the right length bolts
into their rightful place or damage can occur when tightening the bolts.
Use a wrench or ratchet to tighten the mounting bolts in a even cross pattern
and torque to factory specification which is usually between 19 and 22 foot pounds.
If your water pump is equipped with a detachable pulley reinstall the pulley
back onto the pump and insert and tighten the mounting bolts in a cross pattern.
Use a large flat blade screwdriver to hold the pulley from turning while
12. Finish Reassembly
Reinstall the serpentine belt and the fan clutch in the same way it was removed. Again this
would be a good time to replace the belt with a new one since it is off already.
Also many mechanics feel this is a good time to
replace the thermostat,
flush the radiator for safe measure since the cooling system has
already been opened. Reassemble the upper fan shroud and any other plastic clips
and guards. Make sure everything is out of the way of the fan blade area.
13. Refill Coolant
Reinstall the upper and lower radiator hoses and double check the job. Then
start adding coolant while looking under the car for any obvious leaks. Once the
reservoir is full, step back from the engine compartment and start the engine.
Watch the level of the coolant and add more as needed while allowing the engine
to warm up to operating temperature.
Once the engine is warm the thermostat will open and there may be a drop in
the coolant level. After topping the reservoir or radiator off install the
radiator cap with the engine still running. Drive the car for a few days and
then double check the coolant level once the engine has cooled down. This would
be a good time to check the job for leaks.
Watch the Video!
Here is the job being done by one of our mechanics.
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