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. Completely drain the cooling system by opening the radiator drain cock at the bottom of the radiator.
2. If the coolant is dirty, or if there are deposits in the radiator, flush the cooling system before refilling. Refer to Flushing .
3. Remove the radiator pressure cap.

3.1.	Clean the cap.

3.2.	Test the cap. Refer to Thermostat Diagnosis

3.3.	If necessary, replace the cap.

3.4.	Clean the radiator filler neck. Inspect the filler neck.

4. Disconnect the hose from the coolant recovery reservoir. Remove the reservoir. Refer to Coolant Recovery Reservoir Replacement .

4.1.	Clean the outside of the coolant recovery reservoir.

4.2.	Pour out any fluid.

4.3.	Thoroughly clean the inside of the reservoir using soap and water.

4.4.	Thoroughly flush the reservoir with clean water. Drain the reservoir.

5. Install the reservoir. Connect the reservoir hose. Refer to Coolant Recovery Reservoir Replacement .

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).

1. Refill the cooling system with GM Goodwrench® DEX-COOL® or Havoline® DEX-COOL®. To ensure sufficient engine cooling, freezing and corrosion protection, maintain the protection level at -37°C (-34°F) lower. Use a solution that is no more than 70 percent antifreeze.
2. Place the heater and A/C control in any A/C mode except Max and the temperature in the highest setting.
3. Allow the engine to continue idling until the lower radiator to coolant pump hose is hot.
4. Cycle the engine speed up to about 3000 rpm and back to idle five times. Slowly open the bleed valve on the rear of the thermostat housing for approximately 15 seconds to expel any trapped air in the cooling system.
5. After the air has been expelled, fill the radiator. Install the radiator pressure cap, making sure the arrows on the cap line up with the coolant recovery tube.
6. Allow the engine to cool to outside temperature. Check the coolant level in the reservoir.