GM Service Manual Online
For 1990-2009 cars only

Special Tools

    •  J 26568 Coolant and Battery Tester
    •  J 38185 Hose Clamp Pliers

Draining Procedure

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. Follow the steps below in order to remove the surge tank fill cap:
  2. 1.1. Slowly rotate the cap counterclockwise.
    1.2. Stop rotating and allow the hissing to stop.
    1.3. After all the hissing stops, continue turning counterclockwise in order to remove the cap.
  3. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
  4. Place a drain pan under the generator control module coolant pump hose. Refer to Generator Control Module Coolant Pump Hose Replacement .
  5. Using the J 38185 , reposition the generator control module coolant pump hose clamp.
  6. Remove the generator control module coolant pump hose from the coolant pump.
  7. Drain the coolant.
  8. Place a drain pan under the generator control module coolant inlet hose. Refer to Generator Control Module Coolant Inlet Hose Replacement .
  9. Using the J 38185 , reposition the generator control module coolant inlet hose clamp.
  10. Drain the coolant.

Filling Procedure

    Notice: The procedure below must be followed. Improper coolant level could result in a low or high coolant level condition, causing engine damage.

  1. Install the generator control module coolant pump hose. Refer to Generator Control Module Coolant Pump Hose Replacement .
  2. Using the J 38185 , reposition the generator control module coolant pump hose clamp.
  3. Install the generator control module coolant inlet hose. Refer to Generator Control Module Coolant Inlet Hose Replacement .
  4. Using the J 38185 , reposition the generator control module coolant inlet hose clamp.
  5. Lower the vehicle.
  6. Important: Use pre-mixed Dexcool only. Pre-mix DEXCOOL contains the proper 50/50 mixture of DEXCOOL and de-ionized water necessary to prevent corrosion damage to the generator control module internal heat sink. Never use tap water in the hybrid cooling system.

  7. Slowly fill the cooling system with the pre-mixed DEXCOOL. Refer to Approximate Fluid Capacities .
  8. Turn the ignition ON.
  9. As the cooling pumps run, air will purge into the surge tank and the coolant level will drop. Top off the coolant as necessary until the coolant is maintained at the Cold Full line.
  10. Inspect the concentration of the generator control module coolant using the J 26568 .
  11. Install the coolant pressure cap.