Chevrolet produced the 1996 Impala family with the 5.7-liter, 16-valve, fuel-injected engine that produced 260 horsepower and 330 foot-pounds of torque. Power was transmitted to the rear wheels through a four-speed automatic transmission, and braking was controlled through the four-wheel anti-lock brake system. Driver- and passenger-side airbags provided collision protection. Other features, such as the heated mirrors, rear window defroster, leather seats and power-adjusted driver's seat, lent an air of luxury to the car.
Park the Impala on firm, level ground. Place the transmission in "Park" and set the parking brake. Open the hood and allow the engine to cool until the radiator cap is cold to the touch.
Wipe the coolant reservoir cap with a clean shop rag to remove debris that may fall into the reservoir. Remove the cap from the reservoir. Find the radiator drain petcock on the rear of the radiator, at the bottom driver-side corner. Place a catch pan below the petcock and open it by hand. Allow the radiator to drain fully. Close the petcock
Locate the air-bleed valve on the water-pump inlet just above the water pump on the front of the engine. Place a clean shop rag between the air-bleed valve and distributor to prevent fluid from contaminating the distributor. Open the air-bleed valve, using a wrench.
Find the knock sensors in the middle of the engine block on both sides. Disconnect the electrical leads. Slide the catch pan beneath the each knock sensor in turn, and then remove the sensors, using a ratchet and socket. Allow the coolant to drain fully from the engine water jacket in the block.
Install the knock sensors and torque them to 14 foot-pounds, using a foot-pound torque wrench and socket.
Add a 50-50 blend of coolant and distilled water to the coolant reservoir. Observe the coolant leaving the air-bleed valve, and close the valve once air bubbles are no longer apparent in the reservoir. Close the valve, using a wrench.
Start the engine and allow it to idle with the reservoir cap off until the thermostat opens. Open the air-bleed valve, using a wrench, and observe the coolant stream. Close the valve once the coolant stream is free of air bubbles.
Add two coolant supplement sealer pellets to the coolant reservoir. Fill the reservoir until the level is approximately one inch above the "Full Cold" mark. Install the reservoir cap and allow the engine to reach full operating temperature. Check for leaks.
