Engine Cooling System: Maintenance Chevrolet Uplander I

Draining Procedure

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-241684-S36257494482006081100000) in General Information.
2. Place a drain pan under the drain cock.
3. Open the radiator drain cock.
4. Drain the cooling system.
5. Remove the coolant pressure cap.
6. If a complete engine block drain is required, remove the engine drain plugs.
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 «Flushing»(ref-241700-S00202046522006081100000) .

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-241684-S36257494482006081100000) .
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 engine block drain plug.
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. Refer to «Flushing»(ref-241700-S00202046522006081100000) .

Vac-N-Fill Procedure

1. Attach the Van-N-Fill cap to the vehicles coolant fill port.
2. Install the extension hose.
3. Attach the vacuum gauge assembly to the Vac-N-Fill cap.
4. Attach the fill hose to the barb fitting on the vacuum gauge assembly. Ensure that the valve is closed.
5. Pour the coolant mixture into the graduated reservoir.
6. Place the fill hose in the graduated reservoir.
7. Install the vacuum tank on the graduated reservoir with the fill hose routed through the cut-out area in the vacuum tank.
8. Attach the venturi assembly to the vacuum tank.
9. Attach a shop air hose to the venturi assembly. Ensure the valve on the venturi assembly is closed.
10. Attach the vacuum hose to the vacuum gauge assembly and the vacuum tank.
11. Clamp off the overflow hose.
12. Open the valve on the ventui assembly. The vacuum gauge 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 coolant fill port.
15. Slowly open the valve on the vacuum gauge 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»(ref-241700-S08149533912006081100000) .
18. Open the valve on the vacuum gauge assembly. The vacuum gauge will drop as coolant is drawn into the system.
19. Once the vacuum gauge reaches zero, close the valve on the vacuum gauge assembly and repeat steps 11-17. Remove the extension hose.
20. Remove the J 42401 .
21. Detach the Vac-N-Fill cap from the vehicles coolant fill port.
22. Add coolant to the system as necessary.
23. Inspect the concentration of the coolant mixture using J 26568 .
24. Detach the vacuum hose form the vacuum gauge 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.

Flushing

Store used coolant in the proper manner, such as in a used engine coolant holding tank. Do not pour used coolant down a drain. Ethylene glycol antifreeze is a very toxic chemical. Do not dispose of coolant into the sewer system or ground water. This is illegal and ecologically unsound.

Various methods and equipment can be used to flush the cooling system. If special equipment is used, such as a back flusher, follow the manufacturer's instruction. Always remove the thermostat before flushing the cooling system.

When the cooling system becomes contaminated, the cooling system should be flushed thoroughly to remove the contaminants before the engine is seriously damaged.

Flushing Procedure

1. Drain the cooling system. Refer to «Draining and Filling Cooling System (Static Fill)»(ref-241700-S12524063102006081100000) or «Draining and Filling Cooling System (Vac-N-Fill)»(ref-241700-S29801871252006081100000) .
2. Remove the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(ref-241700-S32885562382006081100000) .
3. Clean and flush the coolant recovery reservoir with clean, drinkable water.
4. Install the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(ref-241700-S32885562382006081100000) .
5. Follow the drain and fill procedure using only clean, drinkable water. Refer to «Draining and Filling Cooling System (Static Fill)»(ref-241700-S12524063102006081100000) or «Draining and Filling Cooling System (Vac-N-Fill)»(ref-241700-S29801871252006081100000) .
6. Run the engine for 20 minutes.
7. Stop the engine.
8. Drain the cooling system. Refer to «Draining and Filling Cooling System (Static Fill)»(ref-241700-S12524063102006081100000) or «Draining and Filling Cooling System (Vac-N-Fill)»(ref-241700-S29801871252006081100000) .
9. Repeat the procedure if necessary, until the fluid is nearly colorless.
10. Fill the cooling system. Refer to «Draining and Filling Cooling System (Static Fill)»(ref-241700-S12524063102006081100000) or «Draining and Filling Cooling System (Vac-N-Fill)»(ref-241700-S29801871252006081100000) .