Caution: As long as there is pressure in the cooling system, the temperature can be considerably higher than the boiling temperature of the solution in the radiator without causing the solution to boil. Removal of the pressure cap while the engine is hot and pressure is high will cause the solution to boil instantaneously -- possibly with explosive force -- spewing the solution over the engine, fenders and the person removing the cap.

Caution: An electric fan under the hood can start up even when the engine is not running and can injure you. Keep hands, clothing and tools away from any underhood electric fan.

1. Remove the surge tank pressure cap.

1.1.	Clean the cap.

1.2.	Test the cap.

1.3.	If necessary, replace the cap.

1.4.	Clean the surge tank filler neck. Inspect the filler neck.

2. Remove the front air deflector. Refer to Front Air Deflector Replacement in Body Front End.
3. Open the radiator drain at the bottom of the radiator.
4. Completely drain the cooling system.
5. If the coolant is dirty, or if there are deposits in the radiator, flush the cooling system before refilling. Refer to Flushing .
6. Remove the surge tank. Refer to Radiator Surge Tank Replacement .

6.1.	Clean the outside of the surge tank.

6.2.	Pour out any fluid.

6.3.	Thoroughly clean the inside of the surge tank using soap and water.

6.4.	Thoroughly flush the surge tank with clean water and drain.

7. Install the surge tank. Refer to Radiator Surge Tank Replacement .
8. Close the radiator drain.
9. Install the front air deflector. Refer to Front Air Deflector Replacement in Body Front End.

Notice: Do not add cold water to the cooling system with the engine at or above operating temperature. Adding cold water causes rapid cooling, resulting in possible engine damage.

NOTICE: When adding coolant, it is important that you use GM Goodwrench DEX-COOL® or HAVOLINE® DEX-COOL® coolant. If Coolant other than DEX-COOL® or HAVOLINE® DEX-COOL® is added to the system the engine coolant will require change sooner; at 50 000 km (30,000 mi) or 24 months.

Notice: Do not use a solution stronger than 70 percent antifreeze. Pure antifreeze can freeze at -22°C (-8°F).

Notice: This engine uses DEX-COOL® and GM coolant supplement (sealant) P/N 3634621 specifically designed for use in aluminum engines. Failure to use the engine coolant supplement (sealant) and the approved coolant antifreeze could result in major engine damage. When refilling the cooling system, add three pellets of the engine coolant supplement sealant GM P/N 3634621 to the lower radiator hose.

Important: This engine is not equipped with block drains, 2.5 L (2 Qt) of residual coolant remains in the engine block.

1. Refill the cooling system. In order to ensure sufficient engine cooling, freezing and corrosion protection, maintain the protection level at -37°C (-34°F) or lower.
2. Start the engine.
3. Place the heater and A/C control in any A/C mode except Max and the temperature in the highest setting.
4. Allow the engine to continue idling until the lower radiator to water pump hose is hot.
5. Turn OFF the engine.



6. Allow the engine to cool to outside temperature. Ensure the coolant level in the surge tank is at the proper level (1).