How to Replace a Water Pump on '91 4Runner

At some point, your vehicle's water pump may malfunction, which can cause a variety of symptoms with little or no warning. Therefore, it is wise to replace the water pump on your vehicle before it actually breaks, which will save you money in the long run.
Replacing the water pump on a '91 Toyota 4Runner is a moderately difficult procedure. Due to the vehicle's large engine bay and rear-wheel drive design, the tear down and reassembly is much easier than on other, smaller vehicles.
This job will typically take an afternoon to complete. In order to make the procedure go as quickly as possible, make sure you have all of the necessary parts and supplies before removing any parts from the car. Also, since this procedure deals with the engine cooling system, you need to make sure the car has cooled down before working on it. With a little care and plenty of muscle and elbow grease, your new water pump will be installed in no time.

Instructions

Remove the Radiator

1

Drain the coolant from the radiator. Unscrew the plug at the bottom of the radiator and let it drain. To speed up the process, unscrew the radiator cap to let air flow through while it drains.

2

Remove all of the hoses that connect to the radiator. Remember which hose was attached to the top and bottom of the radiator; you'll need to re-attach them after you've replaced the water pump.

3

Unscrew the radiator shroud from the radiator. The shroud will not fit over the fan when you remove the radiator. After the shroud is free from the radiator, place it over the water pump assembly so the radiator can be removed.

4

Unscrew the radiator from the engine bay. Once all of the screws are removed from the radiator, lift the radiator out of the engine bay. Be careful not to scratch or dent the radiator when removing it.

Remove the Water Pump

5

Remove the power steering and air conditioning belts from the water pump pulley. There is a tensioner for each belt that keeps them tight. Loosening the belt tensioner allows you enough room to slip the belt off of the pulley.

6

Remove the fan and fluid coupling assembly from the water pump pulley.

7

Remove the water pump assembly. There are 6 bolts and 3 nuts that need to be removed. Be careful to keep these bolts and nuts for the re-assembly.

8

Remove the water pump gasket from the engine block. Depending on how old the gasket is, this could take a while. Your local automotive store sells gasket remover that will make the job easier.

Install New Water Pump

9

Put the new gasket in place over the bolts after the engine block is clean. If the gasket did not come with gasket sealant, you can find some at your local automotive store. The gasket sealant is important because it creates an airtight seal between the water pump and the engine. An improper seal will eventually cause a coolant leak or a water pump malfunction.

10

Install the new water pump with the 6 bolts and 3 nuts that you removed earlier. Make sure everything is tightened properly.

11

Install the water pump pulley and replace the belts.

12

Install the fluid coupler and fan.

13

Install the radiator and radiator shroud.

14

Reconnect all of the coolant hoses. It is important to tighten the hose clamps properly. A slight leak due a loose clamp may not be noticed for several hours after adding the new coolant.

15

Add new coolant to the radiator and bleed the coolant hoses appropriately. The vehicle's manual should provide the amount of coolant the radiator and engine need to function properly.

16

Start the vehicle. Listen for any strange sounds and watch out for leaks. If everything looks good, take the car out for a ride and make sure the temperature gauge reaches a normal operating temperature. Anything low or high could signify a problem. Also, if you don't have heat after this procedure, you might need to bleed the coolant hoses some more or add more fluid.