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.

Important: If you do not follow the procedure below, a low or high coolant level condition and/or vehicle damage could result.

1. Park the vehicle on a level surface.
2. Remove the radiator pressure cap:

2.1.	Slowly rotate the cap counterclockwise until the cap reaches the stop.

Do not press down while turning the cap.

2.2.	Allow any residual pressure, (indicated by a hissing sound) , to be relieved.

2.3.	After all the pressure is relieved, press down on the cap and continue to rotate the cap counterclockwise.

3. Open the radiator drain cock.
4. Open the air bleed screw located on the thermostat housing.
5. Allow the system to drain completely.
6. Inspect the engine coolant for the following conditions:

•	Discolored - flush the cooling system. Refer to Flushing .

•	Normal in appearance - continue with the next step.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

7. Close the radiator drain cock.

Tighten
Tighten the radiator drain cock to 2 N·m (18 lb in).

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.

8. Fill half the capacity of the cooling system with 100 percent DEX-COOL® coolant.
9. Slowly add clean drinkable water to the system until the level reaches the base of the fill neck.
10. Start the engine.
11. With the pressure cap still removed, idle the engine until the normal operating temperature is reached.

The radiator inlet hose will become hot.

12. Close the air bleed screw when coolant is visible dripping from the bleed screw.
13. With the engine still idling, add coolant to the radiator until the coolant level reaches the bottom of the fill neck.
14. Install the pressure cap.
15. Rinse away any excess coolant from the engine and engine compartment.