1. Close the radiator drain **** and remove the drain hose.
2. Reinstall engine block drain plugs if previously removed.
O Use pipe sealer GM PIN 12346004 when installing drain plugs.
3. Fill the surge tank to the base of the filler neck.
NOTE: Open the coolant air bleed valve on the top of the thermostat bypass pipe/heater pipe assembly. Once a continuous stream of coolant is expelled from the valve, close the valve.
4. With the pressure cap off, start the engine and let it run until the upper radiator hose starts to get hot.
5. If the coolant level in the surge tank is low, add the proper mix of coolant until the level reaches the full cold line.
6. Install the cap onto the tank with hand tight pressure.
O After servicing the cooling system, an occasional intermittent low coolant light (if equipped) may be encountered during some extreme driving maneuvers. This complaint should be eliminated be removing the surge tank cap and adding coolant to a level just at or above the full cold line when the system is cold.