The 2003 Chevrolet Impala was made with either a 3.4-liter six-cylinder engine or a 3.8-liter six-cylinder engine. Any time the cooling system on either engine is serviced, air must be removed from the system or air pockets will form, affecting the efficiency of the cooling system. The coolant filling and air bleeding process for both engines is the same but must be followed exactly or it will not remove all of the air from the system. The 2003 Impala requires the use of DEXCOOL coolant, which cannot be mixed with any other coolant and has a cooling system capacity of 3 gallons.
Lift the Impala's hood and support it with the hood prop rod. Allow the engine to cool completely before continuing.
Turn the coolant pressure cap counterclockwise a quarter turn. The hissing noise is the pressure being relieved from the cooling system. Once the hissing noise dissipates, remove the coolant pressure cap.
Set the drain pan on the ground in front of the vehicle. Attach the 6-foot section of quarter-inch vacuum tubing onto the coolant bleeder located on the thermostat bypass pipe. Direct the opposite end of the vacuum tubing into the drain pan.
Open the coolant bleeder valve by rotating it counterclockwise with the 5/16-inch line wrench.
Slowly pour fresh 50-50 premixed DEXCOOL coolant into the coolant pressure cap opening. Continue to add coolant until a steady stream of coolant is expelled from the vacuum tubing. Tighten the bleeder valve with the 5/16-inch line wrench.
Top off the cooling system until full. Remove the vacuum tubing from the coolant bleeder valve. Start the engine and idle at 2500 rpm for 45 seconds, then shut off the engine. If the coolant level dropped, add fresh DEXCOOL until the system is full again. Install the coolant pressure cap.
Take the coolant from the drain pan to a repair shop for proper disposal.
