A vehicle's water pump is used to push engine coolant through the cooling system to keep the engine from overheating. In the 1991 Honda Accord the engine itself, through the use of the timing belt, drives the water pump. If the water pump fails the engine could overheat and cause major damage. If this happens, the old water pump will need to be removed and replaced with a new one. In the 1991 Honda Accord, the water pump is located on the left side of the engine just behind the front left tire.
Disconnect the battery from the motor by removing the cable going to the negative pole on the battery. This is to ensure that there is no electricity going to the car so nothing can short.
Empty the coolant from the engine by opening the plug in the bottom of the radiator. Let the coolant drain into a clean container so that it can be re-used after the installation of the new water pump.
Align the timing marks on the engine by turning the crankshaft until cylinder number one reaches top dead center (TDC) of the compression stroke. Take off the timing belt and make sure that the engine doesn't turn at any time during the removal or replacement process.
Unscrew the six bolts holding in the water pump, making sure to keep track of which hole each bolt came from. The bolt heads are 1 mm in diameter.
Pull the water pump and O-ring from the motor to complete the removal process.
Place some sealant on the rubber surface of the new water pump located near the bleed hole to protect it from tearing.
Insert the new O-ring and water pump into the spot where the old pump came from on the motor. Make sure that the holes for the bolts on the new pump are lined up with the holes on the motor.
Replace the six bolts on the new water pump. Use a torque wrench to tighten them to 9 ft.-lbs. of torque.
Replace the timing belt on the engine and pour the coolant from its container back into the radiator. Make sure the engine coolant is completely filled before starting your vehicle.
Reconnect the battery to the motor by connecting the negative wire to the negative battery terminal and start your vehicle. Check for any excessive leaking coming from the newly installed water pump. A small amount of fluid coming from the bleed hole is okay.
