Coolant: Service and Repair

The cooling system should be flushed and refilled using the following recommended procedure:
1. Remove radiator cap when engine is cool by:
^ Slowly rotating cap counterclockwise to detent. (Do not press down while rotating).
^ Wait until any residual pressure (indicated by a hissing sound) is relieved.
^ After all pressure has been relieved, press down on cap while continuing to rotate counterclockwise.

CAUTION: To avoid the danger of being burned, do not remove radiator cap while engine and radiator are still hot, scalding fluid and steam may be blown out under pressure, causing serious bodily injury.

2. Open radiator drain valve, engine drain plug and coolant pipe plugs.

3. Close valve, install engine block drain plug and coolant pipe plugs.

4. Run engine, drain and refill the system, as described in Steps 1, 2 and 3 a sufficient number of times until the drained liquid is nearly colorless.

5. Allow system to drain completely and then close radiator drain valve tightly, and install block and coolant pipe drain plugs.

6. Remove recovery cap leaving hoses in place. Remove coolant recovery tank and empty of fluid. Flush tank with clean water, drain and reinstall.

7. Add enough water and ethylene glycol antifreeze (meeting GM Specification 1825-M) to provide the required cooling, freezing and corrosion protection. Use a solution that is at least 50 percent antifreeze, but no more than 70 percent antifreeze. With the engine off, remove the radiator cap add coolant through the thermostat housing until the coolant reaches the spill point of the radiator neck. Install the radiator and thermostat housing caps. (Do not install thermostat at this time). Install 3 liters (3.2 qts.) of coolant into the coolant reservoir.

8. Run engine for 3 minutes. Accelerate engine to a fast idle for 15-20 seconds. Turn the engine off. Remove the thermostat housing fill cap.
a. Turn the cap slowly to the left until it reaches a "stop." Do not press down while turning the cap.
b. Wait until any remaining pressure (indicated by a hissing sound) is relieved, then press down on the cap and continue turning it to the left.

9. Add coolant to the thermostat housing until it reaches the housing cap seat; install the thermostat and cap making sure that the arrows on the cap line up with the water inlet hose on the thermostat housing.

10. When the engine has cycled through a complete warm-up an4 cool, the coolant in the reservoir sh6uld be adjusted to a level between the add and full lines.

Note: It is the owner's responsibility to keep the freeze protection at a level proportionate with the temperatures which may occur in the area of vehicle operation.

^ Maintain cooling system freeze protection at - 37°C (- 34°F) to ensure protection against corrosion and loss of coolant from boiling even though freezing temperatures are not expected.
^ Add ethylene glycol base coolant that meets GM Specifications 1825-M when coolant additions are required because of coolant loss or to provide additional protection against freezing at temperatures lower than - 37°C (- 34°F).
^ Alcohol or methanol base coolants or plain water are not recommended at any time.

NOTICE: Adding anti-freeze to prevent the coolant from boiling too soon is permissible but too much will affect the freezing point. A solution stronger than 70% anti-freeze should never be used, as the freeze level rises rapidly after this point. Pure anti-freeze will freeze at - 22°C (- 8°F). To assure sufficient engine cooling, the protection level should be maintained to at least - 37°C (- 34°F).