Refilling

1. Close the radiator drain valve. Reinstall all engine block drains.
2. Remove the coolant recovery reservoir and empty. Flush the reservoir with clean water, drain and reinstall.





3. Slowly fill the cooling system through the radiator neck using the following procedure:
^ If the coolant system has been flushed, first add 100 percent ethylene glycol in the amount listed in the illustration for the appropriate engine cooling and heating option. Then slowly add clean water to the system until the level of the coolant mixture has reached the port of the coolant temperature switch. Wait for two minutes and recheck the level of the coolant mixture, add clean water if necessary to restore the coolant mixture level to the port of the coolant temperature switch. Install the coolant temperature switch. Then slowly add clean water to the system until the level of the coolant mixture has reached base of the radiator neck. Wait for two minutes and recheck the level of the coolant mixture, add clean water if necessary to restore the coolant mixture level to the base of the radiator neck.

NOTE:
^ When refilling the engine cooling system, add three engine coolant supplement sealant pellets, GM P/N 3634621 or equivalent, and GM approved new Ethylene Glycol Coolant DEX-COOL(R) GM P/N 9985809.
^ If the cooling system is being refilled ONLY (no flush), a 50 percent ethylene glycol and 50 percent clean water mixture should be used to fill the system. Fill the system until the level of the 50/50 mixture has reached the port of the coolant temperature switch. Wait two minutes and recheck the level of the coolant mixture, add a 50/50 ethylene glycol/water mixture as necessary to restore the coolant mixture level to the port of the coolant temperature switch. Install the coolant temperature switch. Fill the system until the level of the 50/50 mixture has reached the base of the radiator neck. Wait two minutes and recheck the level of the coolant mixture, add a 50/50 ethylene glycol/water mixture as necessary to restore the coolant mixture level to the base of the radiator neck.

4. Install the radiator cap making certain the arrows line up with the overflow tube.
5. Close all air bleeds. DO NOT over-torque the air bleed valve.
^ The air bleed valve is made out of brass.
6. Fill the coolant reservoir with a 50 percent ethylene glycol and a 50 percent clean water coolant mixture. The proper amount of this mixture to be installed into the coolant reservoir is listed below:
^ All engines Add 2.4 liters (2.5 quarts) of a 50/50 mixture of ethylene glycol and clean water to the coolant recovery reservoir.

CAUTION: The low coolant indicator lamp may come on after this procedure. After operating the vehicle so that the engine heats up and cools down three times, if the low coolant indicator lamp does NOT go out, or fails to come on at ignition check and coolant is at the level indicated in step 3. If at any time the "TEMP" warning indicator comes on, immediate action is required.

NOTE: The freeze protection of the engine coolant after the engine heats up and cools down three times using a thermohydrometer to ensure proper freeze -37°C (-34°F) protection. Obtain the coolant mixture for the inspection from the base of the radiator neck, NOT from the coolant recovery reservoir.