Cooling System Draining and Filling (Static Fill)

Draining and Filling Cooling System (LS4 Static Fill)

Draining Procedure
^ Tools Required
- J 26568 Coolant and Battery Tester

Caution: 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.

1. Important: Draining the cooling system with the pressure cap installed will syphon the coolant from the overflow tank.

Remove the coolant pressure cap.
2. Place a drain pan under the drain cock.
3. Open the radiator drain cock.
4. Drain the cooling system.
5. If a complete engine block drain is required, remove the drain plugs from the engine block. Refer to Draining Fluids and Oil Filter Removal for the 5.3L engine.
6. Inspect the coolant.
7. Follow the appropriate procedure based on the condition of the coolant.
^ Normal in appearance-Follow the filling procedure.
^ Discolored-Follow the flush procedure.

Filling Procedure

1. Notice: Refer to Fastener Notice.

Close the radiator drain cock.
2. If a complete engine block drain was required, install the drain plugs to the engine block. Refer to Draining Fluids and Oil Filter Removal for the 5.3L engine.

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

Slowly fill the cooling system with a 50/50 coolant mixture until the coolant level is visible and stable.
4. Install the pressure cap loosely (threaded on about one turn).
5. Start the engine and raise the engine speed to 2,500 RPM and hold it there for 40 seconds, then shut engine off.
6. Remove the pressure cap and fill the coolant system until the level is visible and stable.
7. Install the pressure cap loosely (threaded on about one turn).
8. Start the engine and raise the engine speed to 2,500 RPM and hold it there for 30 seconds, then shut engine off.
9. Remove the pressure cap and fill the coolant system until the level is visible and stable.
10. Install the pressure cap loosely (threaded on about one turn).
11. Start the engine and raise the engine speed to 2,500 RPM and hold it there for 20 seconds, then shut engine off.
12. Remove the pressure cap and fill the coolant system until the level is visible and stable.
13. Install the pressure cap, fully threaded on.
14. Fill the coolant recovery bottle to the indicator line, then add 400 milliliters (13.5 ounces) more.
15. Start the engine and run it above 2500 RPM until it is hot enough to open the thermostat, this will allow the trapped air to be purged from the engine.
16. Complete a series of three, four-second-duration idles with four-second-duration 3000 RPM cycles.
17. Turn the engine off and allow it to cool down.
18. Fill the coolant recovery bottle to the indicator line.
19. Inspect the concentration of the engine coolant using the J 26568.
20. Rinse away any excess coolant from the engine and the engine compartment.