Cooling System Draining and Filling LY7 Static Fill

Warning: In order to avoid personal injury, do not remove the cap or open the cooling system drains from a hot system. Allow the system to cool first.





Note: A 7.6 liter (8 quart) coolant container will be needed.

1. Place the coolant container under the radiator drain cock.



2. Remove the surge tank cap from the surge tank and the coolant will drain from the system.



3. If necessary drain the engine block.
4. Inspect the coolant.
5. Follow the appropriate procedure based on the condition of the coolant.

•	Normal in appearance--Follow the filling procedure.

•	Discolored--Follow the flush procedure. Refer to Coolant System Flushing .

Caution: All entrapped air must be purged from the powertrain cooling system before the final coolant level can be determined. Proper coolant level is critical to avoid engine damage.

Note: The vehicle must be level when filling the cooling system.

1. Slowly add a mixture of 50/50 DEX-COOL antifreeze and clean water to the coolant surge tank.
2. Start the engine and check for leaks.
3. Run the engine and cycle the vehicle from idle to 3,000 RPM in 30-second intervals until the engine cooling fan comes ON. The engine cooling fan turns ON at approximately 102°C (216°F). Repeat this process twice before the engine is turned OFF.
4. Return the engine to idle, and idle for 30 seconds, then turn the engine OFF.
5. Allow the vehicle to cool before adding additional coolant.

Note: The level in the surge tank will return into the cold fill range once the vehicle cools.

6. Add additional coolant to the surge tank until the level is approximately 13 mm (0.5 in) above the surge tank seam.
7. Install the coolant surge tank cap.

Cooling System Draining and Filling LY7 GE 47716 Fill

Special Tools

Warning: In order to avoid personal injury, do not remove the cap or open the cooling system drains from a hot system. Allow the system to cool first.





Note: A 7.6 liter (8 qt) coolant container will be needed.

1. Place the coolant container under the radiator drain cock located at the bottom of the right radiator end tank.
2. Open the drain valve to start the flow of coolant. Coolant will drain slowly until the surge tank cap is removed.



3. Remove the surge tank cap from the surge tank. Allow the coolant to drain from the system.
4. Close the drain valve once the coolant has drained from the radiator.



5. Additional coolant can be drained from the engine by removing the engine block drain plug.
6. Install the engine block drain plug once the coolant has drained from the engine.
7. Inspect the coolant.
8. Follow the appropriate procedure based on the condition of the coolant.

•	Normal in appearance--Follow the filling procedure.

•	Discolored--Follow the flush procedure. Refer to Coolant System Flushing .

Warning: To avoid being burned, do not remove the radiator cap or surge tank cap while the engine is hot. The cooling system will release scalding fluid and steam under pressure if radiator cap or surge tank cap is removed while the engine and radiator are still hot.

Note: To prevent boiling of the coolant/water mixture in the vehicle cooling system, do not apply vacuum to a cooling system above 49°C (120°F). The tool will not operate properly when the coolant is boiling.




1. Install J-42401-2 into the surge tank fill neck.
2. Install J-42401-3 to the surge tank fill neck.
3. Attach the Vac N Fill cap to the J-42401-3.



4. Attach the vacuum gage assembly to the Vac N Fill cap.



5. Attach the fill hose to the barb fitting on the vacuum gage assembly.

Ensure that the valve is closed.





Note: Use a 50/50 mixture of DEX-COOL antifreeze and clean, drinkable water.

Always use more coolant than necessary. This will eliminate air from being drawn into the cooling system.
6. Pour the coolant mixture into the graduated reservoir.
7. Place the fill hose in the graduated reservoir.

Note: Prior to installing the vacuum tank onto the graduated reservoir, ensure that the drain valve located on the bottom of the tank is closed.

8. Install the vacuum tank on the graduated reservoir with the fill hose routed through the cut-out area in the vacuum tank.



9. Attach the venturi assembly to the vacuum tank.



10. Attach a shop air hose to the venturi assembly.

Ensure the valve on the venturi assembly is closed.




11. Attach the vacuum hose to the vacuum gage assembly and the vacuum tank.



12. Open the valve on the venturi assembly. The vacuum gage will begin to rise and a hissing noise will be present.



13. Continue to draw vacuum until the needle stops rising. This should be 610-660 mm Hg (24-26 in Hg).

Cooling hoses may start to collapse. This is normal due to vacuum draw.

14. To aid in the fill process, position the graduated reservoir above the surge tank.



15. Slowly open the valve on the vacuum gage assembly. When the coolant reaches the top of the fill hose, close the valve. This will eliminate air from the fill hose.
16. Close the valve on the venturi assembly.
17. If there is a suspected leak in the cooling system, allow the system to stabilize under vacuum and monitor for vacuum loss.

If vacuum loss is observed, refer to Loss of Coolant .

18. Open the valve on the vacuum gage assembly. The vacuum gage will drop as coolant is drawn into the system.



19. Once the vacuum gage reaches zero, close the valve on the vacuum gage assembly and repeat steps 12-18.



20. Detach the Vac N Fill cap from the J-42401-3.
21. Remove J-42401-2 from the surge tank fill neck.
22. Add coolant to the system as necessary.
23. Inspect the concentration of the coolant mixture using J 26568 tester .

Note: After filling the cooling system, the extraction hose can be used to remove excess coolant to achieve the proper coolant level.

24. Detach the vacuum hose from the vacuum gage assembly.
25. Attach the extraction hose to the vacuum hose.



26. Open the valve on the venturi assembly to start a vacuum draw.



27. Use the extraction hose to draw out coolant to the proper level.
28. The vacuum tank has a drain valve on the bottom of the tank. Open the valve to drain coolant from the vacuum tank into a suitable container for disposal.