Draining and Filling Cooling Systems

Draining Procedure

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.

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

1. Park the vehicle on a level surface.
2. Follow the steps below to remove the radiator pressure cap:
^ Slowly rotate the cap counterclockwise until the cap reaches the stop. Do not press down while turning the radiator pressure cap.
^ Wait until any remaining pressure, indicated by a hissing sound, is relieved.
^ After all the pressure is relieved, press down on the cap and continue to rotate the pressure cap counterclockwise.
3. Open the radiator drain cock.
4. Remove the engine block coolant drain hole plugs.
5. Inspect the engine coolant:
^ Discolored-follow the flush procedure below.
^ Normal in appearance-Continue with the next step.
6. Allow the system to drain completely.

Filling Procedure

Notice: Refer to Fastener Notice in Service Precautions.

1. Close the radiator drain cock.
^ Tighten the radiator drain cock to 2 Nm (18 lb in).
2. Install the coolant drain hole plugs.
^ Tighten the drain hole plugs to 60 Nm (44 lb ft).
3. Add enough water to fill the coolant system.
4. Run the engine until the thermostat opens.
5. Stop the engine. Repeat the draining procedure until the drained fluid is colorless.
6. Remove, clean, and reinstall the coolant recovery reservoir. Refer to Coolant Recovery Reservoir Replacement.
7. Complete the following steps in order to fill the coolant system:
7.1. Fill the radiator to below the fill neck.
7.2. Fill the coolant recovery reservoir to the FULL HOT mark.
7.3. Install the coolant recovery reservoir cap.
8. With the radiator pressure cap removed, run the engine until normal operating temperature is reached. The radiator inlet hose will become hot.
9. With the engine idling, add coolant to the radiator until the coolant level reaches the bottom of the fill neck.
10. Install the pressure cap.
11. After the engine reaches normal operating temperature, check for coolant leaks.