Toyota started producing the Prius in Japan in 1997, and the car was introduced into the United States in 2001. The Prius is considered a hybrid car, meaning that it is powered by a small gasoline engine and an electric motor. Depending on the road conditions and driver input, the switch between gasoline and electric power is automatic and completely seamless to the driver. The cooling system on the Prius needs regular maintenance for proper operation. If coolant is leaking on your water pump, the pump probably must be replaced.
Raise the front of the Prius by driving it onto a set of car ramps. Set the parking brake and chock the rear wheels.
Place a drain pan beneath the radiator petcock. From underneath the car, open the plastic radiator petcock by turning it carefully in a counterclockwise motion using a pair of pliers, and let the old coolant pour into the drain pan below.
Close the radiator petcock by twisting it in a clockwise motion with the pliers, being careful not to over-tighten it.
Open the hood. Locate and loosen the idler pulley bolt with a wrench, then pull off the alternator and air conditioner belts by hand.
Use wrenches to remove the three bolts and two nuts that attach the water pump to the engine block. While doing this, keep the water pump pulley from rotating by using the special tool. Carefully remove the water pump assembly from the engine block by hand.
Clean any remnants of gasket or sealant from the water pump mating surface on the engine block by wiping it with a shop towel and acetone. Avoid using a scraper, as this may gouge the engine block.
Apply a few dabs of gasket sealer to hold the new water pump gasket to the engine block, and remount the water pump to the engine block using the original bolts and nuts.
Reinstall the water pump pulley by holding the pulley into position with the special tool and reattaching the three holding bolts with a wrench.
Reinstall the alternator and air conditioner belts by hand over the pulleys, and tighten the idler pulley with a wrench.
Twist off the radiator cap in a counterclockwise motion. Fill the radiator with a 50/50 mix of antifreeze and distilled water. The radiator capacity is 4.5 quarts for a car with an automatic transmission and 4.7 quarts for a car with a manual transmission. Replace the radiator cap by simultaneously pushing down on it and turning it in a clockwise direction.
Start the engine and let it warm up. Visually inspect the water pump and surrounding area for coolant leaks. If you detect any leaks, shut off the engine and tighten all connections.
Check the radiator level, and top it off with a 50/50 coolant mixture if necessary.
Remove the wheel chocks, and back the car off the ramps.
