The 1998 Chevy S10 uses a water pump to circulate coolant through the system to cool the engine while it is running. The pump draws cooled fluid from the radiator and pushes it continuously through the engine. If the water pump stops functioning, no fluid will circulate and the engine will overheat, possibly resulting in damaged engine parts and expensive repairs. In the even of failure, the water pump must be replaced immediately.
Remove the fan from the front of the engine block. There are four bolts that hold the fan in place on the water pump pulley. Loosen these bolts with a socket and ratchet, then remove the fan from the pulley and place it to the side.
Place the drip pan under the radiator stop cock, and turn the stop cock counter clockwise to drain the coolant. The stop cock is located on the bottom of the reservoir, on the back of the radiator near the center. Allow all of the coolant to drain.
Remove the water pump pulley. Hold the pulley in place and use a socket and ratchet to remove the four bolts holding it onto the water pump. Place the pulley to the side once it is removed.
Move the drip pan so that it is under the water pump. Using a pair of pliers, loosen the clamps that hold the hoses on the water pump. Allow the fluid to drain from the hoses into the drip pan.
Use a socket and ratchet to remove the four bolts holding the water pump in place. Remove the water pump from the engine compartment.
Remove any parts of the old gasket from the front of the engine block where the old water pump was seated.
Place the new gasket in the indented area that you removed the old water pump from.
Place the water pump in the area and hold it flush against the gasket. Place the four bolts through the holes in the water pump, and tighten with a socket and ratchet.
Squeeze the clamps on the hoses with a pair of pliers and replace the hoses back on the appropriate ports of the water pump.
Put the pulley back in place on the water pump and use the socket and ratchet to replace and tighten the bolts.
Hold the fan in place against the front of the pulley. Align the holes in the fan with the holes in the pulley. Start the retaining bolts by hand and tighten with the socket and ratchet.
Place a ratchet with a 3/8-inch drive into the square hole on the belt tensioner. The tensioner is located on the left hand side of the engine bay. Rotate the ratchet counterclockwise to loosen it. Route the belt around the water pump pulley again and make sure that the belt is correctly routed around the other pulleys. Your truck has a diagram on the front lip of the engine bay above the grill with the proper routing. Put the tension back on the belt by moving the tensioner clockwise.
Turn the stop cock on the bottom of the radiator clockwise the close it off. Remove the radiator cap and fill the radiator with coolant to the top of the fins. These are the metal parts that you can see inside the radiator. Place the radiator cap back on securely.
