On this vehicle you must first remove the timing belt and timing belt cover to access the water pump. Since you will have everything apart I highly recommend that you replace the timing belt and tensioner along with the water pump. Here is the procedure. Please let me know if you have any questions. Thanks.
1. Disconnect the negative cable of the battery. Drain the coolant. Remove all accessory drive belts and remove the water pump pulley. Remove the crankshaft pulley bolt and remove the pulley only.
2. Remove the upper and lower timing belt covers. If this is the DOHC model then there will be an upper, middle, and lower timing belt cover. Disconnect the spark plug wires and remove the spark plugs.
3. Rotate the crankshaft clockwise until No. 1 piston is at TDC of the compression stroke. Make sure that camshaft sprocket and crankshaft sprocket timing marks align. (See the first picture below.)
4. If the timing belt is to be reused, mark the direction of timing belt rotation before removal. Loosen the timing belt tensioner lock bolt. Move the tensioner away from the belt with the spring fully extended. Tighten the tensioner bolt while the belt tension is released and remove the timing belt.
5. Remove the water pump inlet pipe and gasket. Remove the "O" ring from the coolant bypass pipe. Remove the water pump bolts and remove the water pump. Remove the gasket and clean the gasket mating surface of the engine block.
6. After making sure all gasket mating surfaces are perfectly clean, install the new gasket on the coolant inlet pipe. Install the water pump and inlet pipe. To complete installation just reverse the removal procedure. Make sure the bolts are tightened to the correct torque specifications. (14-19 ft lbs.)
7. Now for installing the timing belt, make sure the crankshaft and camshaft timing marks are still aligned. Install the belt around the crankshaft sprocket. Keeping the belt pulled tight on the right side (facing the engine), route the belt around the camshaft sprocket(s).
8. Loosen the timing belt tensioner lock bolt, and allow the spring to apply tension on the belt. Snug the tensioner lock bolt. Rotate the crankshaft clockwise 2 complete revolutions. Make sure the timing marks align. If timing marks are not aligned, remove the belt and realign all timing marks and repeat installation procedure.
9. Check timing belt deflection. Do this with 22 lbs of pressure applied to the belt. Timing belt deflection should be .36-.45" (9.0-10.7mm). If the timing belt deflection is not within specification, repeat steps 2 and 3 or replace the timing belt tensioner spring. If the timing belt deflection is within specification, reverse the removal procedure to complete the installation.