In order to keep the engine cool, all vehicles use a coolant circulation system. The coolant transfers the heat away from the engine, flows to the radiator, and allows the radiator to dissipate the heat. But in order to move the fluid around the system, your car needs a properly working water pump. This pump also moves hot coolant into your cabin heating system so you can have a warm air on those cold days.
Bring the vehicle to a complete stop. Turn off the engine, allow the car to cool and open the bonnet. Remove the negative battery cable, loosening the cable clamp with a wrench. Move the cable to the side.
Find the coolant drain plug on the bottom of the radiator at the front of the vehicle. Put a drain pan underneath the plug. Use pliers to turn the drain plug counterclockwise to allow the coolant to drain from the radiator. After the fluid is done draining, close the drain port by turning it clockwise with the pliers.
Loosen the tension on the accessory drive belt. Use a ratchet to rotate the tension adjustment bolt until the belt can be removed. The bolt is located on the tensioner pulley on the passenger side of the engine
Remove the timing belt covers from the centre and upper part of the engine on the passenger side of the engine compartment. These are removed by loosening the fasteners with a ratchet.
Turn the engine crankshaft to the top dead centre (TDC) position with a ratchet. The crankshaft is the pulley at the bottom of the engine on the passenger side. The TDC position is marked on the edge of the crankshaft pulley. Rotate the crankshaft with the ratchet until it lines up with the corresponding mark on the engine block.
Loosen the bolt on the timing belt tension pulley with a ratchet and pull the timing belt off by hand. Remove the bolt holding the timing belt guard with a ratchet.
Loosen and remove all water pump retaining bolts with a ratchet. Pull the water pump from the engine. Throw away the O-ring and clean the water pump seating surface with a rag.
Coat the new O-ring with a bit of coolant and attach it to the water pump. Position the water pump on the engine and push it in.
Insert the water pump retaining bolts and tighten them to 11 foot-lbs. with a torque wrench. Also insert and tighten the timing guard bolt to 15 foot-lbs. with the torque wrench.
Push the timing belt back on to the pulleys by hand. Reinstall the centre and upper timing belt covers and secure the bolts with a ratchet. Route the accessory drive belt around the tension pulley and tighten down the pulley with a ratchet.
Fill the coolant reservoir with antifreeze until the fluid is at the "full" line. Reattach the negative battery cable and tighten down the clamp with a wrench.
Start the engine and check for leaks in the water pump area. Allow the engine to heat up to normal operating temperature and recheck the fluid level in the coolant reservoir. Refill if necessary. Turn off the vehicle and close the bonnet.